Thoughts about Crossovers in general

by Kathryn A

(last revised 17 May 2007)

What is it that makes one crossover more do-able than another? What kind of structure does a Crossover story require? What things don't work?

The Device

All crossovers need a (plot) Device, something which brings the two universes together in order for the crossover to happen. It depends on what kind of universe it is as to what Device can be used, but here are some common ones:

The same (or later) time and place

The shows happen to be set at around the same time and place, such as England-in-the-eighties, or at the same place and a similar time (for example, one show set in the seventies, another in the eighties) where one lot of characters has merely grown a little older, or at the same time in a similar place, where one lot of characters has simply travelled overseas, for example.

  • UFO/Professionals
  • Equalizer/Stingray/Blind Fury
  • Tomorrow People/Champions
  • Man From U.N.C.L.E./The Avengers
  • The Sentinel/Highlander
  • Smallville/Buffy
  • Joan of Arcadia/Heroes


Time travel, Time-space travel

One lot of characters has travelled in time (or space-time) usually using a machine or device, deliberately or accidentally, and ended up where the other lot of characters is. This is the usual method for Doctor Who, who can travel almost anywhere you want him to go. Star Trek has already had people stumbling across ancient alien time travel machines, or shooting their space ship very fast around a gravity well, and travelling back in time.

Hanging Around

A character may travel from the past to the future at the normal rate, if there's some compelling reason that they're still alive after a few centuries. There are two chief methods for this: (a) immortality (of the Highlander kind, the vampiric kind or some other kind) or (b) suspended animation (human cryogenics, alien devices or magic spells).

Space travel

One lot comes from somewhere else by space-ship. I suppose you could say that was really similar-time-&-place, though. One example is a Battlestar Galactica/Blake's 7 crossover where the Galacticans finally find Earth, and it is the Federation.

Teleport malfunction

This can be used by universes with teleport to whisk their unfortunate victim either back in time (nobody seems to want to go forward!) or into a parallel universe.

  • Blake's 7/20th Century
  • Star Trek/20th Century
  • Star Trek - Mirror, Mirror

Inter-universal rift

An inter-universal rift, strange cloud, black hole-white hole, CVE(*) or other strange phenomenon may link two parallel universes, grabbing any passing spaceship, space-time-ship, teleport beam or even someone going on a morning stroll, and thrusting them into a parallel universe, where they spend the rest of the plot trying to get back again...

(*) "Charged Vacuum Emboitment" -- this was the technobabble used in Doctor Who to explain how the TARDIS was zapped into another universe during the series of adventures which ended up with Romana going off with the Tharil...

Omnipotent being

Yep, you just got zapped by Q.

Something In Common

In order for two universes to cross over, there needs to be a pivotal point, some place where they can meet, some knot upon which to hang the juxtaposition. This can be the same as the Device, but what I am talking about here is the kind of thing that catches the imagination of the writer and prompts them to say "Hey, wouldn't that be a good idea!"

Common names

Things or people may have the same names, but different origins. One may be conceived to be the ancestor of the other, in time-travel scenarios.

  • Blake's 7 Federation - Star Trek Federation
  • Highlander Watchers - Buffy Watchers

Common faces

If the same actor has appeared in more than one loved show, it may be an irresistible temptation to play "swap" or "doppleganger" with the two characters. Or, the scenario may just be to swap the actual actors and the characters they played. Some common actors:

  • Michael Keating - Blake's 7/Doctor Who
  • Joanna Lumley - Sapphire & Steel/The New Avengers
  • David McCallum - Sapphire & Steel/The Man From U.N.C.L.E./ The Invisible Man/Babylon 5/VR.5
  • Patrick McNee - The (New) Avengers/The Man From UNCLE (15 years later)
  • Anthony Steward Head - VR.5/Buffy the Vampire Slayer
  • Richard Burgi - The Sentinel/One West Waikiki
  • Richard Dean Anderson - MacGyver/Stargate

Common blood

Similar to the doppleganger situation, one could make it that certain characters are related -- but this requires particular care, because one has to have a very good reason why this "relative" has never been mentioned before. It can often end up being just too cheesy and awful.

Similarly, the "old flame" connection can be used, but should be treated with caution. TPTB overuse this device themselves, there's no reason why we ought to make the same mistakes. If a character has already had an old flame in canon, then no more should be given.

Common interests

Characters may have common interests which bring them together, like Vila & Scotty with booze, or Avon & Spock with computers, or Ace & Dayna with explosives, or Richie and Garibaldi with motorcycles, or Blair and Daniel with ancient and obscure manuscripts... (Or even Hiro Nakamura and John Crichton with Star Trek references)

Common talents

This isn't quite the same as common interests, and is more likely to be in usable for characters who have unusual talents, such as enhanced senses or psi powers.

  • (senses) The Champions, The Sentinel, Dark Angel, X-Men (Wolverine)
  • (telepathy) The Champions, Tomorrow People, X-Men
  • (telekinesis) Tomorrow People, X-Men, Heroes, Star Wars, Stargate SG-1 (Cassie)

Common technology

Some devices/powers are too similar not to exploit their similarity. Teleports, telepathy (from lots of places), dilithium crystals/feldon crystals from Star Trek and Blake's 7, heck, I even wondered about a Doctor Who/Darkover crossover because of the similarity between the Mind's Eyes of "Snakedance" and the Matrix crystals of Darkover.

Common wierdness

This is sort of the fantasy equivalent to "common technology"; shows with a more fantasy bent could have things in common, like Vampires (Buffy the Vampire Slayer and Forever Knight), magic and goulies (Buffy, Charmed, Poltergeist The Legacy, Friday the Thirteenth, Harry Potter), ghosts (Real Ghost Busters, Buffy etc) or some otherworldly dream dimension (Sandman, Matrix (the TV series)).

Common scenery

Someone already suggested, wouldn't it be fun to write a crossover where all the series that get filmed in BBC quarries all meet. I haven't come across that idea before, though. Do BBC monster props count as scenery? Where did Dorian get that Sea Devil in his basement...? Why are all the worlds connected by the Stargate either pine forests or sandy deserts?

Whose Crossover Is It Anyway?

Some universes are more able to provide Devices than others, if we are talking about non-same-time-place Devices. In that case, the style of plot, or at least the plot resolution, tends to be dominated by the universe which provided the Device. Since the Doctor can travel anywhere in his TARDIS, he leaves by the same means at the end, like he always does. Star Trek tends to go for time travel and inter-universal rifts, though it may not be the actual Enterprise that goes through them, it may be some other ship (such as the Liberator) which actually uses the Device. Sapphire & Steel can travel in time, but only to deal with temporal breaks, so if they turn up, you already know what kind of plot you must have.

Some universes are very difficult to cross over with believably, because they lack Devices of their own, and their background is completely incompatible with many things except a parallel universe scenario. I can't imagine, say, a Survivors/Who Framed Roger Rabbit crossover, but a Survivors/Professionals crossover would be possible if you made Survivors set after the Professionals (I know The Professionals was made after Survivors, but Survivors [at least in the first two episodes, that's all I've seen] doesn't say when it is set, and you can't argue from fashion any more, since retro fashions are the vogue right now...). Sometimes one can cross over two incompatible universes by borrowing a Device from a third; for example Danger Man/Danger Mouse via the Device from Who Framed Roger Rabbit... (how weird can you get?).

Of course most of the incompatible crossovers wouldn't be conceived of anyway, because they lack that something-in-common which would make it interesting and worthwhile to cross them over in the first place. I guess that wouldn't stop some people - particularly if it was a parody-style crossover whose main intent was to be ridiculous, rather than serious. With parodies, all bets are off, and all of the above probably doesn't apply.

Things to Avoid

There are, alas, many badly-written crossovers out there, enough to make many people swear off the genre altogether. While all fanfic has the risk of being badly written, there are a few extra potholes lying in wait for the crossover writer.

Ubermensch and Canon-Sues

Yes, I know you think your favourite character is neat and Kewl, but that doesn't mean that s/he has to overshadow everyone else, or be portrayed as too good to be true. This can be an especial danger with crossovers, because the author may like one show more than the other. But, frankly, if the only reason one is writing the story is to show how much better/stronger/faster/smarter/prettier the folks from one universe are than the folks from the other, then it is better to keep the story in one's bottom drawer. And yes, that does include the endless debates about whether the Enterprise would be able to fight off the Death Star, and other arguments of similar ilk.

Lack of Necessity

Sometimes one wishes to write a crossover just because it would be fun to see these characters interact. That's fair enough, but the plot needs to be twice as wide to accomodate twice as many characters. Otherwise you just have a bunch of people standing around doing nothing, or two people doing the job of one person. If the plot doesn't need a character, that character doesn't have a good enough reason to be there. For example, I once read an otherwise good Sentinel/Quantum Leap crossover Sam leapt into Jim... and the person who had the information needed to solve the problem was... Jim. Which meant that everyone would have been better off if Sam hadn't Leaped into Jim in the first place -- zap, there goes the plot.

Instant Friends

The opposite problem one lot wiping the floor with the other lot, is where one likes all the characters so much, that it seems just the perfect thing for them all to get on like a house on fire as soon as they meet. Unfortunately, even if a character is as friendly and outgoing as Blair Sandburg or Hiro Nakamura, he's still liable to be interacting with other characters who are as wary and suspicious as Jim Ellison or Kerr Avon. Remember what your characters don't know. And one thing they definitely don't know is that the other bunch are Good Guys too.

And even if they do know, or quickly sort out, that the other lot are Good Guys, that doesn't mean that they are going to make friends with each other any quicker than they would if the other lot were just Random J. Character from off the street. Indeed, one good discipline when writing a crossover is to consider that one lot of characters are simply "guest-stars" (aka guest-characters) for that "episode".

Spilling The Beans

Almost all crossovers have secrets; things that one bunch of characters doesn't know about the other bunch, things that the characters generally keep quiet about. This can be anything from Immortality, the existance of Vampires, the "super" powers that characters have (Slayer strength, psi powers, magic powers, heightened senses, being Superman etc), the existance of aliens, or the Stargate, and so on.

One big mistake that is too commonly made is that almost as soon as both sets of characters meet, or as soon as they're asked the question, they just go and tell the other lot all their secrets. Slightly less egregious is where, under circumstances where they've been forced to admit there are secrets (such as an Immortal dying and reviving in front of someone) they go and spill all the beans, instead of limiting it to as few as possible. For example, even if Methos was forced to reveal he was an Immortal, there is no way in a thousand years that he'd just tell them that he was Methos, the oldest Immortal. I mean, how out of character can you get? I remember one really good story I read, where Methos was captured by an Evil Government Conspiracy and confronted with documented evidence of his immortality -- and he did the sensible thing: he lied through his teeth, backing it up with half-truths. That's in character.

Not Spilling The Beans

The opposite problem to spilling the beans too much is not spilling them at all. I don't mean by this that the secrets have to be revealed -- it can be very fun watching these characters being oblivious of each others secrets, or tiptoeing around them without revealing them. What I'm referring to is where the beans have already been spilt, but offstage: either the story begins with everybody knowing everything (with no previous story to refer back to) or the bean-spilling is glossed over with a "and then they explained everything to each other" sentence. I admit that this is more a personal preference than a real error, but I do find that the bean-spilling event (if the beans are going to be spilled at all) is one of my favourite parts of crossovers, because it can be fun just watching them all react to these incredible secrets in-character. And sometimes it doesn't really matter, because the story is a drabble or something like that, and the focus of the story is simply on established interaction. But it becomes frustrating if the vigniette is something which implies the existance of other stories which haven't been written.

See Also