Ethan Mars is introduced in Heavy Rain's prologue as a successful architect living an idyllic life, married to a loving wife and the father of two young boys, Jason and Shaun. However, this life is shattered when Jason is run over by a car and Ethan is badly injured and slips into a coma. The main narrative of Heavy Rain picks up two years after this tragedy. Haunted by Jason's death, Ethan's life has completely fallen apart. Divorced, he lives in a small, run-down house with joint custody of Shaun. The car accident that put him in a coma and the trauma of losing Jason have also inflicted a number of issues on his mental state, including enoclophobia, or a paralyzing fear of crowds, depression, and infrequent blackouts.
Ethan's life takes an even darker turn when he takes Shaun to the park and suffers another blackout. When he returns to his senses, he discovers that Shaun has vanished, and eventually learns that he has become the latest victim of the Origami Killer. To complicate matters, because of Ethan's mental and emotional problems, he and others doubt his sanity and come to suspect that he is in fact the Origami Killer.
When Ethan opens a letter that he receives from the Origami killer he is instructed to retrieve the contents of a train station locker. Inside, he finds a package that, among other items, contains a collection of origami figurines. Each figure in the box is numbered, and when unfolded reveals an address to which Ethan must travel in order to undertake a trial. By completing each trial successfully, Ethan earns a clue that will lead him to Jason, but the trials are also meant to tax Ethan mentally, physically, and spiritually. These trials are:
- The Bear: Ethan must drive for five miles into oncoming freeway traffic in order to prove that he is brave enough to look for his son.
- The Butterfly: Ethan must crawl on broken glass and walk through an electrified maze in order to prove that he is strong enough to push forward.
- The Lizard: Ethan has five minutes to cut off the distal end of a finger using one of many tools found in an abandoned apartment (including a knife, pliers, saw, scissors, and hatchet), proving that he is willing to sacrifice part of himself to save his son.
- The Shark: Ethan has to kill someone specified by the killer and take a picture of the body, proving that he is willing to do whatever it takes in order to save his son.
- The Rat: Ethan must make the ultimate sacrifice in order to save his son.
Points where Ethan can die
- The Old Warehouse (Ethan murdered during the police operation, DVD/Blu-Ray/PSP ending)
- Epilogue - Helpless (By hanging himself in jail)
- Epilogue - Tears in Rain (By shooting himself by Shaun's grave in front of Madison)
- Epilogue - Origami Blues (By shooting himself in his hotel room)
Shaun is sad over his father's death. Then, he leaves with his mother, Grace. Madison and/or Scott can be shown in a tree depending who survives.
A New Start
Ethan and Shaun are moving in to a new house. The latter is searching for a place for his room and tells his father that they will be together forever. Ethan chases his son in a playful manner afterwards.
A New Life
Ethan, Madison, and Shaun are moving in to a new house. The latter finds a place for his room. When Ethan asks if the house is perfect, Madison replies that it is. She wishes that the whole experience they did is only a dream. Just then, Shaun teases her and Ethan, causing the latter to chase him playfully.
Ethan is shown in his bedroom, saddened over Shaun's death. He commits suicide by shooting himself in the head.
Tears in the Rain
Ethan and Madison are shown in Shaun's grave. The latter convinces the former to go on with his life with her and that he may have her child. Ethan tells Madison that he loves his sons more than anything else in the world and tells her that he will be with her in a few minutes. Just then, Madison has witness Ethan committing suicide by shooting himself in the head.
Ethan is arrested after being accused to be the Origami Killer. Because of Shaun's death, he hangs himself.
Ethan is released after proven to be innocent. His ex-wife, Grace comes with their son, Shaun. She decided to let them get reunited.