While on their journey home, Voyager is plundered by space pirates, who use a special transporter to steal machinery from passing ships. Captain Janeway and Tuvok pursue them to their homeworld, where the holodeck program of Leonardo Da Vinci helps Captain Janeway get Voyager's items back.

The crew experiences vivid nightmares, all containing the same mysterious alien. Chakotay must stay awake to lead an attack against a species that lives in the dreams of Voyager's crew.