“If I don’t give my kidney to somebody this week, will somebody die waiting for it?” The answer to this question, posed in Samantha Smith’s film, is unequivocally “yes.” Despite that, ethical and practical riddles surround the willingness of a living donor to undergo surgery and bodily mutilation to help a complete stranger. Smith doesn’t delve deeply into these questions. She simply tells the story of a kidney donor and recipient — individuals strikingly different from one another — leaving the audience to ponder the conundrum of more people needing kidneys than kidneys available. As the final credits roll, the viewer may wonder: “What am I doing walking around with two healthy kidneys?”