Twinsanity is also called as Goodbye Gemini, Dziewczyna na pozegnanie。

Unnaturally close twin siblings Jacki and Julian become enmeshed in the swinging London scene, where they attract the attention of the heavily endebted gambler Clive. Seeing a way out of his debts, Clive sets Julian up for a blackmail scheme, setting in motion a nightmarish sequence of events.