There comes a time when teenagers learn something new about their parents. Sometimes it’s gross out-bedroom facts, for instance. And sometimes it’s that their folks are…vampires.

The Radleys are a normal, mundane, suburban family in Scotland (I think, but it might be England) who go to work and school each day. But we learn early on that mom and Dad (superb Damian Lewis and Kelly MacDonald) are longtime vampires who, with the online help of a kind of AA for bloodsuckers, have completely abstained from biting necks for years.

It’s not easy fighting their primal instincts, but they make a go of it, not wanting their old habits to affect their friends, family, and especially their kids. Ah, but wouldn’t you know it – one of them finally breaks down, setting off a chain of consequences, some pretty damn funny and others not so much.

Dad calls in his twin bother (also played by Damian in a great dual role) to give counsel and somehow help, even though the raggedy brother never gave up the practice and, it will be revealed, has a dark connection to this nuclear family that was a secret until now.

What I enjoyed was just how normal these characters were in abnormal circumstances. It’s like watching Fred and Barney bowling with a boulder; everything is normal except for the one thing that isn’t, and that’s where the laughs and gentle scares come in.

I usually don’t go for so-called Horror-Comedies because they always end up lacking in one category or the other. Here, and with the help of some really good teen actors, the snickers and shivers both come through, but it was the laughs that did it for me.

The Radleys, now in theaters, on digital, and on-demand | 3 out of 4 Stars | rated R | Under two hours