Full story
Danny Rand walks back into New York barefoot, looking like a drifter. Everyone thought he died at age ten in a plane crash in the Himalayas that killed his parents. In fact, monks rescued him and raised him in K'un-Lun, a mystical city in another dimension, where he trained in martial arts for fifteen years and earned the title of Iron Fist. That lets him focus his chi into his fist and strike with supernatural force.
Danny wants his place back at Rand Enterprises, the company his father founded with Harold Meachum. It's now run by Harold's kids, Ward and Joy, Danny's childhood friends, who don't believe he's alive. Ward has him committed to a psychiatric hospital. What neither of them knows is that Harold didn't die of cancer years ago. He's alive, hiding in a penthouse and pulling Ward's strings. The Hand brought him back to life and made him their prisoner.
Danny proves who he is, returns to the company, and starts stirring things up with ethical decisions that cost money. He meets Colleen Wing, who runs a dojo, and the two grow close. Danny learns that the Hand is using Rand Enterprises to move heroin, on Madame Gao's orders. He confronts Gao, who reveals she arranged the plane crash to stop his father from shutting the operation down. Then Bakuto shows up, leader of another faction of the Hand, claiming he wants to help. Bakuto was Colleen's teacher, and she had been part of the Hand without knowing what it really was.
Colleen chooses Danny, and Claire Temple joins the fight too. Ward, addicted and cornered, kills his own father, but Harold comes back to life again, more unstable each time. The monk Davos, Danny's childhood friend from K'un-Lun, arrives saying Danny abandoned his duty to protect the city. Harold, meanwhile, tries to pin everything on Ward.
In the end, Harold shows his true face and tries to kill both Danny and Ward. Ward shoots his father and has the body cremated so he can't be revived. Danny and Colleen travel to K'un-Lun and find the entrance empty and littered with Hand bodies: the city is gone. Joy, furious with Danny and her brother, teams up with Davos. K'un-Lun's fate and Joy's side are left open.