Through an unlikely chain of events, a middle-aged home owner is lured into a time machine that sends him several hours into the past; once he emerges from it, he discovers he must engineer the same chain of events and lure his earlier self along the same path or he’ll cease to exist. The idea of time travel creating multiple selves dates at least as far back as Robert A. Heinlein’s 1941 short story “By His Bootstraps,” but in practical terms it’s so confusing one can imagine why moviemakers have shied away from it. Spanish writer-director Nacho Vigalondo explores it just enough to keep this 2007 thriller moving, and Karra Elejalde is entirely convincing as the unwilling time traveler, who finds himself threatened by not only his past self but his future one as well. In Spanish with subtitles. 88 min.