Like Neil LaBute’s Possession, this melodrama features a lot of historical sleuthing in the present intercut with a lot of repressive sexual chicanery in the 1800s, as an English photographer (Catherine McCormack) sails to the Isles of Shoals off the New Hampshire coast to investigate the long-ago murders of two young women. But whereas Possession was relatively light on its feet, this is so overloaded from the outset that it can only sink. If all that interests you is the solution to the mystery story (which is pretty good, featuring Sarah Polley, Vinessa Shaw, Ciaran Hinds, and the late Katrin Cartlidge), then this will keep you engaged roughly half the time. If you’re more interested in the sexual machinations on board the sailboat (with Sean Penn as the photographer’s famous-poet husband, Josh Lucas as his brother, and Elizabeth Hurley as the latter’s flirtatious English girlfriend), then you may be irritated by the flashbacks that keep interrupting them. Even if you like both stories, you may be puzzled by director Kathryn Bigelow’s overwrought mixmaster effects. Screenwriters Alice Arlen and Christopher Kyle adapted a novel by Anita Shreve. 114 min. (JR)