A terrible toothache causes Jack Robin to stop his automobile in front of the home of Dorothy Mason. Noticing a flat tire, Jack attaches his automatic pump and forgets about it as he listens enthralled to Dorothy's singing. When the sound of the burst tire brings Dorothy running out, Jack feigns injury so he can be nursed by her. After he leaves the house, and Dorothy's father discovers some important invention plans missing, Harlan Graves, Dorothy's suitor, suggests that Jack stole them. Jack, suspecting Graves, breaks into Graves' home to clear himself and meets a real burglar, "Spider" Kelly, who adopts Jack as his guide. They blow up a safe at a house party where Jack suspects the plans to be hidden. The papers are found, Graves is arrested and Spider, disappointed that Jack made such a mess in blowing the safe, goes off, leaving Dorothy and Jack happily alone.
