Season 4 of the series picks up where Season 3 ended – with Harry (Alan Tudyk) and his baby Bridget stuck in prison on the Grey Moonbase and a new alien shapeshifter impersonating him back on Earth.

If we've learnt one thing about shapeshifters over the years, it's to keep a close eye on the dog! Whereas Odo used a canine disguise so he could arrest Quark no matter the century, Geordi's phoney ...

Members of your crew have been replaced by an alien shapeshifter intent on causing confusion, sabotaging the ship, and killing everyone. Root out the 'Impostor' or fall victim to its murderous designs ...

A term used in fiction to describe a whole host of ghostly/undead creatures — the ones from Stargate Atlantis will definitely suck the life out of you — the Wraith in Star Trek are telepathic ...