“Uninvited” is a Filipino revenge thriller, a slow but solid B-picture slicked up to pass for an A-feature.

Vilma Santos stars as a grieving mother who sets out to avenge a student-daughter “defiled” and murdered by a mob boss, a mobster with a lot of underlings who make such assaults possible.

Lilia has gotten herself invited to Boss Guilly’s (Aga Muhlach) birthday party. She passes herself off as the head of a foundation that flattered the mobster’s moll/wife (Mylene Dizon) with a donation to her favorite charity. But Lilia, stylishly dressed in black, has more than just mingling on her mind.

The father of another victim of Guilly’s murderous gang suggests she add his child to her “lawyer’s” brief of accusations.

“A lawyer won’t be necessary for my plan,” she says (in Tagalog, Spanish and English, with subtitles).

Fiftysomething Vilma tracks her progress with an interior monologue. Sometimes it’s for herself — “A good thing I don’t have my gun with me.” And sometimes she’s talking to her dead daughter Lily (Gabby Padilla). “Just four left, sweetie.”

Dodo Dayao’s script sets the story in the birthday party fictive present, with long flashbacks showing Lilia’s loss, her despair at her daughter’s seemingly random grabbed-from-the-street fate and the ways she plans for revenge.

Director Dan Villegas takes his sweet time getting around to those flashbacks and that plan. It’s a slow-pokey thriller that takes an hour of introductions — constantly changing points of view showing us the depravity of the “boss,” the venality of his lieutenants, his wife, his daughter (Nadine Lustre), a rival, a dirty cop and others — before the revenge and the “plan” come together.

No, it’s not wholly logical. But a little old lady — Santos is 70+ and thus a bit old to be playing the mother of a coed — with a big knife and a furious temper is still somebody to be reckoned with.

The avenger may pause for muttered condemnations and accusations, but once the killing starts this short thriller starts to play as intended — taut, mean and bloody.

The motivation isn’t new. The villain is generic. And the bloodshed isn’t particularly inventive. But running over a murderous accomplice, and then backing over him a couple of times, is always going to play as satisfying.

Rating: TV-MA, graphic violence including rape, drug abuse, profanity

Cast: Vilma Santos, Aga Muhlach, Nadine Lustre, Mylene Dizon,
RK Bagatsing, Ketchup Eusebio, Gio Alvarez, Cholo Barretto and Gabby Padilla.

Credits: Directed by Dan Villegas, scripted by Dodo Dayao. A Warner Bros./Netflix release.

Runnin time: 1:33