Plot summary
While the Federation starship Enterprise is en route to their planned destination, ship's sensors detect a lone shuttlepod drifting through empty space with no power or fuel reserves. When Lt. Worf and Commander Riker use the tractor beam to bring it into the shuttlebay, they find it has the same name and registry as an Enterprise shuttle. Inside is a double of Captain Picard, barely clinging to life. After the double is brought to sickbay for treatment, Lt. Commander Data and Chief Engineer La Forge discover that the shuttle's internal clock is about six hours ahead of the ship's chronometer which means that the shuttle, and therefore Picard's double, is from six hours into the future. They recover a very poor quality sensor log video that shows the Enterprise falling into an energy vortex and being destroyed after the shuttle is launched.
Chief Medical Officer Dr. Pulaski determines that the incoherent double's biological functions are out of sync, but are improving as the future Picard draws nearer to his own time. Picard orders that his future self be revived, but is unsuccessful in extracting any information from him. Picard is disquieted at the idea that he would abandon his ship and its crew. The crew members decide to continue on their current course. They are suddenly stopped by the vortex seen in the shuttle log and are unable to escape. Scans emanating from the vortex appear to focus on Picard and an energy beam strikes him leading him to theorize that there is an intelligence controlling the vortex which seems to be interested in him personally, and that his double left the ship to draw its attention.
Picard's double, now almost completely aware and coherent, sets out to leave the Enterprise as he did before. Picard follows him, asserting that there must have been another option. As the double is boarding the shuttlepod, Picard proclaims that the cycle will be broken and kills him with a phaser. Picard returns to the bridge and orders that the Enterprise fly straight into the center of the vortex. The Enterprise comes through the other side into normal space, and the doubles of Picard and the shuttlepod disappear. The Enterprise resumes its course.
Credits
Adapted from Wikipedia contributors, Time Squared (Star Trek: The Next Generation). Paragraphs and formatting adjusted; illustrations, reference markers, block quotations and non-story material omitted.