The Tesseract, is a 2003 thriller film starring Jonathan Rhys-Meyers. Based on the novel of the same name by Alex Garland, it is directed by Oxide Pang.
The film examines four seemingly unconnected lives brought together through a theft in a Bangkok hotel room (unlike the novel which is set in Manila). The interactions of an English drug dealer, an English psychologist, a Thai assassin, and an abused 13-year-old boy demonstrate that life is so complex that even the smallest events can have enormous, even fatal consequences (i.e. the butterfly effect).
Sean, a runner for a drug gang, has checked into room 303 at the seedy, rundown Heaven Hotel in Bangkok, to await arrival of a package of heroin. Another guest is Rosa, psychologist who is researching slum children, on the floor below (room 202). In the next room, 203, is Lita, a female assassin who is waiting to intercept the package Sean is waiting for. Tying them all together, is the 13-year-old bellboy, Wit, a streetwise, light-fingered kid.