At the time of his 118th birthday, Nemo Nobody (Jared Leto in Benjamin Button makeup) relates his memories to a journalist (Daniel Mays). It’s 2092, and Nemo is the last mortal in a sexless future where “stem cell-compatible pigs” have made it possible for humans to regenerate indefinitely. Naturally, he’s the subject of much curiosity, though confusion prevents him from painting a clear picture of the past. Nemo narrates a voyage through several permutations of his life, following alternate paths. He chooses to grow up with each of his divorcing parents (Natasha Little and Rhys Ifans); has three separate and mutually canceling lifelong romances (Juno Temple grows into Diane Kruger; Clare Stone becomes Sarah Polley; Audrey Giacomini becomes Linh Dam Pham); and experiences various brushes with death. As if the Cloud Atlas-level juggling act weren’t enough, Belgian writer-director Jaco Van Dormael throws in a hypnosis conceit and, courtesy of Nemo’s sometime work as a writer, fiction within the fiction. In one iteration, Nemo appears as a TV scientist who lectures on string theory and entropy. The character’s name alludes to both Jules Verne and The Odyssey, but Mr. Nobody’s expansive literary ambitions turn out to have a powerful ordering principle: sentimentality.