Plot

A string of bizarre illnesses afflicts the Voyager crew. The Doctor and Seven of Nine uncover a team of alien researchers existing out of phase performing medical experiments on the ship's crew.

After Voyager investigates a binary pulsar system (and while B'Elanna's and Tom's clandestine trysts become the talk of the ship), severe genetic ailments begin dropping the crew, with Capt. Janeway herself suffering insomnia and worsening headaches. Recent proximity to the pulsars raises suspicions, but when B'Elanna and the Doctor simultaneously come under attack as they near the truth, the Doctor realizes Voyager has been invaded by unseen aliens with designs on the crew and covertly elicits Seven of Nine's help to expose them.—statmanjeff