AllMovie

The worlds of the 23rd century and the 20th century collide in this episode of the landmark sci-fi series, when an unintentional trip into a time warp sends the starship Enterprise into orbit around Earth circa 1967. The future visitors attempt to hide their presence but are detected by the American Air Force. They evade most of their pursuers, but one pilot, Captain John Christopher, approaches so closely that his plane is destroyed. Christopher is beamed aboard the Enterprise at the last moment, however, and given a glimpse of the world to come. Captain Kirk is then faced with the difficult decision of determining Christopher's fate, fearful that no matter which option he selects -- allowing Christopher to return to the 20th century after his glimpse of the future or taking Christopher into the 23rd century, causing his disappearance from Earth -- will change the future for the worse.