Flatliners is a science fiction movie which stars Kiefer Sutherland as the character of Nelson, Kevin Bacon as David, Julia Roberts as Rachel, Oliver Platt as Randall and William Baldwin as Joe. This group of young people attend a college where they study medicine. One day, Nelson brings up the subject of dying in regards to how long a person could be dead and still be brought back to life. The term flatlining is used in medical circles to describe when there is no recorded brain activity. The discussion leads Nelson to conduct his own experiment by enlisting the help of his fellow medical school friends.
Nelson is the first to undergo the process of flatlining in a controlled group setting. Before going under, the group agrees upon the length of time to allow Nelson to flatline before resuscitating him. Once Nelson is brought back from a state of death, the others in the group want to experience the same journey into the after life that Nelson did. The competitive spirit between certain members in the group leads them to lengthen the amount of time they are flatlining. The increased amount of time each person is left in a dead state becomes more dangerous as it is harder to bring them back.
The experiment in flatlining has some unexpected consequences. When Nelson goes into the dead state, his spirit travels through the afterlife where he encounters a scene from his teen years. After he is brought back he begins experiencing some strange phenomena in his every day life. He believes he is being followed by some unseen character. The strange phenomena also shows up in the lives of the other members of the group after they have journeyed to into the afterlife.
The members begin discussing the experiences they had on the other side. They often encountered unpleasant scenes from previous times in their lives. Nelson's experience seems to have drawn a spirit from the other side into his present life. He continues to flatline in an attempt to understand what is happening with the spirit who has entered his life.