LIKE many of the recent spate of films aimed at the Christian market, Michael Landon Jr.’s “The Last Sin Eater,” a religious-themed period thriller filmed on beautiful locations in Utah, is more than happy to preach to the converted.

The less devout may find this tale of a 10-year-old (Liana Liberato) looking for forgiveness in 1860s Appalachia – after the death of her little sister – a 2 ½ hour, marginally coherent slog.

The cast includes Oscar winner Louise Fletcher (Nurse Ratched herself) and Henry Thomas of “E.T.,” and the special effects look like they were executed on somebody’s laptop.

THE LAST SIN EATER

* 1/2

Running time: 142 minutes. Rated PG-13 (violence). At the Empire, 42nd Street and Eighth Avenue.