Mickey, Donald, and Goofy run a locksmith business in their apartment. Mickey gets a call from Minnie telling him about an emergency. The trio tries to get out, but they find that their key is missing. Goofy tries to check his keychain, but only manages to rattle off some lame puns. Goofy then takes out the spare key hidden under, but he and Donald fight over it and it falls through the door's mail slot. The three try to reel it back in through the window above the door and end up causing trouble for various people in the city and catch a big fish.
Mickey tries a different tactic: using a bobby-pin to pick the lock, but he instead goes through several doors hidden behind it, ending with him discovering Clarabelle Cow taking a bath. Goofy decides to call a locksmith and calls their own phone number, which causes Goofy to have an argument with himself. The three then decide to ram the door down with Goofy as the battering ram. Mickey and Donald successfully push him through, but they bounce off of Clara Cluck's busom and get propelled outside their window, causing them to fall to the ground. Minnie then drives by to tell Mickey that she left his key at her house. Donald and Goofy look at him angrily as Goofy acknowledges that the ending to this cartoon is "kind of door-key".