LAKE HUNTINGTON, NY — In “Betrayal,” the “end is just the beginning.”

River Rep presents four performances of Harold Pinter’s “magnetic masterpiece,” running two Saturdays, October 3 and 10, at 8 p.m.; and two Sundays, October 4 and 11, at 2 p.m. All performances are held at the Delaware Valley Opera Center, 6692 Rte. 52 in Lake Huntington.

Presented in reverse chronological order, “Betrayal” focuses on the affair between Emma (who is married to Robert) and Jerry (who is best friends with Robert). With “poetic precision and rich humor, the complexities of the human heart” are explored in this, “the greatest, and the most moving, of all Pinter’s plays,” according to The Telegraph.

River Rep ensemble members Arthur Aulisi (“The Catastrophist”), Donna Jean Fogel (“Every Brilliant Thing”) and Christopher Peditto (“Art”) form the “eternal triangle.” The show is directed by Eliza Foss with Thomas Cambridge.

Purchase tickets at www.tickettailor.com/events/riverreptheatre/2331136.