Schisms

Riker is worn out despite sleeping a full night, and other crew members report fatigue, odd anxieties and strange reactions to everyday objects. Realising they share the same fragments of memory, several of them gather with Troi on the holodeck and slowly rebuild what they half recall: a dark room with an examination table. Crusher then finds evidence that Riker's arm was severed and reattached. Two crew members vanish, and one is later found dead, with blood turned to a liquid polymer. The crew trace tetryon readings to a growing subspace rift in a cargo bay, through which unknown aliens have been abducting people for experiments. Riker lets himself be taken while carrying a homing device. He wakes on the alien table, rescues the missing crew member and leaps back through the rift just before the Enterprise seals it.