The Dark Horse is based on the real-life story of
Genesis Potini, a brilliant New Zealand chess player who suffered from severe bipolar disorder. The film begins with him walking down a street in the rain, before walking into an antique store and playing a chess game with himself. He has flashbacks of being taught chess by his older brother, and eventually is taken away by police officers to a hospital because of his mental state. He is released into the care of his brother Ariki, who allows him to sleep in his son's room. Upon hearing about a chess club run by his old chess buddy Noble Keelan, he goes around to his house early in the morning to ask to join. He is told he can only do so if he promises to not "rock the boat." Genesis meets the Eastern Knights Chess club in a shed where he learns that they only have one chess board, and the kids are not particularly motivated. He introduces himself and discloses that he wants to lead them to the Junior National Championships in
Auckland, something Noble is initially frustrated with Genesis about. Mana, Ariki's son, followed him to the club, and it is revealed that he will be
patched into his father's Gang, the Vagrants, on his birthday. He is given over to Mutt to harden him up. Ariki, believing that Genesis could interfere with this process asks him to leave. Genesis begins sleeping on the monument on
Kaiti Hill, and leading meetings at the Chess club, now held at the
marae with new chess sets. Mana, though initially hostile towards Genesis begins to see him more regularly, and joins the chess club. Mana reveals that he has been abused and urinated on by Mutt as part of his gang initiation. He also has a V tattooed on his face. The mother of one of the members of Eastern Knights finds out that Genesis is homeless, and refuses to let her son participate, sending him into another mental breakdown. Sandy allows him to sleep at a friend's house, and they all prepare to go to Auckland for the championship. Mana realizes he cannot come as it is on the day that he will be patched, and leaves angrily. Genesis attempts to reason with Ariki, but he refuses to let Mana leave. On the day they leave for Auckland, Genesis stops at the monument to pick up a distraught Mana, and says that Ariki has allowed him to come. They go to Auckland, and all the members of Eastern Knights lose their games apart from Michael and Mana. That night, Mana reveals that he knows Genesis lied about him having permission to come, but that Mana knows his father is dying. He ends up losing his match the next day, but Michael goes on to compete in the final. Genesis repeatedly calls out during the final, and has to be sent outside, but Michael ends up winning the final. Ariki arrives shortly after, and punches Genesis before he yells at Mana to get in the car. The Eastern Knights travel back to Gisborne, and Genesis is visibly upset. He goes over to his brother's to find his nephew, who is unconscious with a black eye. It is revealed that he has just been patched, and Mutt begins beating Genesis, but is stopped by Ariki. Genesis removes Mana's jacket, and they walk out together, being followed and verbally abused by Mutt. Other members of the Gang begin beating Mutt, and Genesis and Mana leave. The closing montage reveals that the Eastern Knights chess club is still being run, and that Genesis died in 2011. ==Cast==