Photonic aliens enter a holodeck serial.
Spatial distortions trap Voyager and lock Tom Paris and Harry Kim's Captain Proton holodeck adventure, a homage to 1930s science fiction serials, into running. Photonic aliens from another dimension slip into the program, take it for reality, and go to war with its villain, Doctor Chaotica, whose holographic death ray can actually kill them, threatening the ship as well.
Unable to simply switch the program off, the crew play along. The Doctor becomes the President of Earth to talk with the aliens, and Janeway takes on the role of Arachnia, Queen of the Spider People, to get close to Chaotica by agreeing to marry him. She lowers his lightning shield, and Captain Proton destroys the death ray, letting the aliens leave and freeing Voyager. The fifth-season episode is a black-and-white comedy and a loving tribute to old serials, and Kate Mulgrew's turn as Arachnia is one of its highlights.