Killing your parents and covering it up? Sounds like black comedy hour, and this Canadian production generally pays off its promise of Grand Guignol humor despite a rickety production that doesn't quite know when to quit.

The four titular siblings are the progeny of two proverbially awful parents, both of whom have been remarried so much that none of the siblings are actually related by blood. When one of the siblings decides to tinker with the brakes on mom and dad's car, the wicked stepparents end up dead in a ravine. They coolly try to cover up the crime (er, incident), only to end up deeper and deeper in their manufactured morass.

You've never seen a group of kids this dark and moody. Slap some black lipstick on them and they're perfect goths -- even the precocious 10-year-old, with her Coke bottle glasses and obsession with death. But other than severe psychological dysfunction, they're all relatively boilerplate characters. Big brother is the caretaker and looking forward to getting out of the house. The oldest daughter is a slut that's slept with the school basketball team. You get the idea.

The scenario they're in isn't exactly new, and ultimately it feels a bit more like Weekend at Bernie's than A Simple Plan, and that's too bad. Some judicious rewrites and a few injections of action could have made Siblings (oh, and a better title, too) into quite the cult comedy.