10 Episodes That Every Sci-Fi Show* Must Have

2 The Alternate Universe Episode

Star Trek’s “Mirror Mirror”

What’s more fun than watching your favourite TV show? How about watching it when it’s set in another reality, where all your familiar cast-members are completely different people doing completely different things?

The Big Daddy of this concept is, of course, Star Trek, whose 1967 episode “Mirror, Mirror” effectively invented the sub-genre on television (and introduced the world to the idea that goatee beards were evil – a fact Futurama explored with relish).

Many, many shows, even the ones that are supposed to be “serious”, have utilised the AU device: whether the episodes in question are set in a parallel universe (all the Star Trek spin-offs have their own episodes set in the “Mirror, Mirror” universe), a world changed by a spell (Buffy‘s “The Wish”) or one created just to make the viewers laugh (Supernatural‘s “The French Mistake”).

Let’s face it, watching people we know and love doing crazy, other-universe things is always a scream. And goatees are evil.

Good Universe: Fringe, countless episodes

Bit of a cheat, this, because Fringe doesn’t actually have a single AU episode. Instead it has many of them, all dotted throughout the series, right up until eventually they become absorbed into the main show and we flick back and forth with gleeful abandon.

At first we merely had glimpses and hints of this other world until we hit the penultimate episode of season two, “Over There Part 1”, which was set entirely in another dimension and even had its own set of opening titles.

This new dimension featured a red-headed Olivia, characters who were dead in our world running around as though nothing had happened, and an alternate, totally sane Walter who became known as “Walternate”. For puns like that, Fringe deserves all the awards. Ever.

Honourable mention: Red Dwarf, which piled on AU episodes as though they were going out of style, and deserves a mention for Ace Rimmer, if nothing else

Bad universe: Lost season six

Across the first five years of Lost, viewers had become accustomed to the show giving us flashbacks to times past and then flash-forwards to times future. The sixth season did something drastic, flashing sideways to show a brand-new, parallel universe in which all our beloved characters had entirely different lives that had very little to do with what was going on in the main plot.

While some of it was interesting (Sawyer as a cop?), ultimately it proved to be completely pointless in the grand scheme of things as we realised all the characters were dead anyway and we’d simply been watching the writers pissing about. Proof that while AU storylines can be fun, there really needs to be a point to them.