When the U.S.S. Enterprise encounters a Federation shuttlecraft cartwheeling out of control through space, the starship pulls it into the shuttle bay.

Riker discovers that the shuttlecraft belongs to the U.S.S. Enterprise, and Dr. Pulaski finds an unconscious double of Picard inside. Captain Picard accompanies his double to sickbay, where Troi explains that the double really is Picard, but from another time. Data tells Picard that the shuttle's on-board clock shows it to be just six hours ahead of the U.S.S. Enterprise.

Scenes taken by the shuttle camera as it departed show the U.S.S. Enterprise surrounded by a whirlpool of energy. The double, frightened and confused in a nightmare world of his own, is unable to convey any information about the impending danger, and a scan of the area reveals nothing similar to the force filmed by the shuttle camera. Picard begins to doubt himself and worries that the judgment he made, as his double in the future, may have left him and his crew in a never-ending cycle of torment.

Suddenly, the whirlpool is upon them. Picard orders Geordi to take the U.S.S. Enterprise away at warp speed, but when it is unable to move, the U.S.S. Enterprise is forced to shut down before it is torn apart by the strain. The whirlpool lashes a tongue of energy which strikes each Picard, leading Troi to explain to Picard that the energy only wants him. Learning of his double's resolve to again leave the ship, Picard decides that they will never be able to move forward until the cycle is broken. He orders the U.S.S. Enterprise to charge directly into the vortex. After a tense moment, the double, the shuttle and the whirlpool disappear, leaving the Enterprise alone and on course again.