Brock decides a picnic is in order. Ash volunteers to fetch the firewood with Pikachu, but the Electric-type is fast asleep. Instead, Ash decides to take Chikorita. Meanwhile, Team Rocket finds themselves walking through various empty hallways when they come across a Magnemite. Four more Magnemite appear, and together they attack with their electricity, sending Team Rocket fleeing. As Ash and Chikorita are walking across the field, they find the building, with the door still open. When the two enter, the door suddenly slams shut, trapping them inside. Ash begins calling for help and his friends come running. Brock notices that the building’s electric lock is damaged and tells Ash that he’ll call the Electric company for assistance. Ash tries to get the door open without any luck; however, Chikorita spots a map of the complex and has Ash looks at it. They go downstairs to check out the place. Upon looking through various empty halls, Ash and Chikorita are attacked by a swarm of Magnemite and a Magneton. Team Rocket watches the squabble, but Jigglypuff soon arrives. Fearing that it is going to sing, James takes away her microphone and tosses it to Jessie, who then throws it towards the Magnemite to give them some time. The microphone rolls to Ash’s feet, and Jigglypuff rushes at him to retrieve its precious item. Ash realizes there is a destroyed shutter behind him, so he runs through it and down a fleet of stairs. Moments later, Jigglypuff manages to get her microphone and Sings, putting all of the Magnet Pokémon to sleep.
(Source: Bulbapedia)