Mathilde, a 17-year-old aspiring astronaut, is seriously injured while tinkering with a homemade rocket prototype. Once set on becoming the next Valentina Tereshkova — the first woman in space — she suddenly finds herself living with the loss of an arm. Sent to a rehabilitation centre for young amputees, Mathilde goes through the many stages of recovery and slowly learns how to move forward and flourish despite her disability.