What is the plotline of American horror comedy film Gremlins?

Gremlins is a 1984 American comedy-horror film directed by Joe Dante, written by Chris Columbus, and produced by Steven Spielberg. The film tells the story of Billy Peltzer (Zach Galligan), a young man who is given a strange creature called a Mogwai as a pet. The Mogwai, named Gizmo, multiplies and spawns other Mogwai, who eventually turn into destructive gremlins. The gremlins terrorize the town of Kingston Falls, Pennsylvania, on Christmas Eve.

The film begins with Billy receiving Gizmo as a gift from his father, Rand (Hoyt Axton), who bought him from a mysterious Chinese man in Chinatown. The man warns Billy that the Mogwai must never be exposed to sunlight, water, or food after midnight. Billy accidentally breaks these rules, and the Mogwai multiply into five: Gizmo, Stripe (Frank Welker), Mohawk (Howie Mandel), George (Dick Miller), and Lenny (Robert Picardo).

The gremlins cause chaos in Billy's house and eventually escape. They take over the town, destroying property and causing havoc. Billy and his girlfriend, Kate (Phoebe Cates), try to stop the gremlins with the help of Gizmo and a scientist named Dr. Taylor (Glynis Barber).

In the end, Billy and Kate defeat the gremlins by exposing them to sunlight. The gremlins melt and disappear, and the town is restored to normal.