A Nanny’s Revenge Saturday, 8:30 p.m., Lifetime

Now that Lifetime has launched its own meta-back-patting series “My Life Is a Lifetime Movie” (Wednesdays at 10 p.m.) to plumb the true stories behind the network’s beloved melodrama-splosions, it’s safe to say the Lifetime Movie is having a moment. Tonight’s little doozy, starring Jodi Lyn O’Keefe (as seen on “Prison Break” and “Two and a Half Men”) seems custom formulated for fans of . . . well, vengeful nannies. There will be (fake) blood.