The children are on an archaeological dig and Cartman finds a magic triangle, but throws it away. Kyle picks it up and gets media attention for his discovery. Kyle takes it home and hides it. At school, Leonard Maltin asks Chef is he has seen Barbra Streisand around. Meanwhile, the boys are making a snowman and are visited by Ms. Streisand. She asks them about the triangle. Chef and Leonard Maltin search for the children and/or Barbra Streisand. Barbra in the meantime reveals that she has the companion triangle, hoping to complete the set and allowing for the "dawn of Zinthar."
Cartman breaks into Kyle's bedroom to get the triangle back. Kyle gives it to him. Chef and Leonard Maltin keep looking for Streisand's mountain condo. Chef demands to know what it is all about. Matlin tells him about Streisand's plan to get the other triangle, join it with the one she has completing the "The Diamond of Pantios" and allowing her to become Mecha-Streisand. Streisand tries to trick the boys out of the triangle. Cartman agrees to sell her the triangle. Back in Hollywood, Sidney Poitier hears about "The Triangle of Zinthar" being found. Streisand has the boys held captive, trying to get the location of the triangle from them. Maltin and Chef are about to give up the search, when Maltin senses her presence. Cartman gives up the triangle and the "The Diamond of Pantios" is completed and Streisand transforms into Mecha-Streisand.
Mecha-Streisand starts reeking havoc on the town of South Park. Maltin and Chef find the boys and discover that Streisand has completed the triangle. Maltin needs to get down to business, so he asks Chef to call Robert Smith of The Cure for additional help. The military (with Uncle Jimbo and Ned) try attacking Mecha-Streisand to no avail. Leonard Maltin arrives in town and transforms himself into a super-being that looks kind of like "Ultraman". Kenny dies and then Sidney Poitier arrives on the scene, transforming himself into a super-being that looks kind of like "Gamera." Maltin and Poitier try attacking Mecha-Streisand, but are no match for Mecha-Streisand. Robert Smith arrives on the scene and transforms himself into a super-being that looks kind of like "Mothra." Using his "Robot Punch", Smith manages to knock the "The Diamond of Pantios" out of Mecha-Streisand allow him to defeat her by throwing her into outer space, where she explodes.
The boys throw the two triangles away, but Ike picks them out of the trash, creating Mecha-Ike as the episode closes.
Kenny dies when a tetherball he hits swings around and grabs him by the throat thus hanging him.