The plot is similar to the episode "War Without End" of Babylon 5:
Several of the main characters enter a temporal rift in space. When one of them (Captain John Sheridan) loses his "time stabilizer" device, he is said to be "unstuck in time". He disappears physically and travels into the future. Later when he briefly reappears, the character Ambassador Delenn, played by Mira Furlan (Danielle Rousseau), gives her own time stabilizer to him. She then becomes "unstuck in time" herself.