powered by AFI
Teenager Hank Parker wants to join the Marines, but cannot convince the recruitment officer that he is old enough. On the same day, Al Haines, the older brother of Hank's girl friend Betty, enlists and goes to say goodbye to the gang of crooks with whom he has been involved. When Al arrives at the office of gang leader Brock, he innocently handles a gun that henchmen Tony and Dutch are cleaning, and Brock tells him that the previous night, when Al was drunk, he passed out after killing a thug named Matt Herman. Brock then shows him Herman's body and remarks that his fingerprints now on the gun could convict Al of murder. Al realizes that he is being framed, but his concern for Betty makes him agree to spy for Brock while he is stationed in San Diego. That night, at a goodbye dinner for Al, Tony and Dutch show up, and Betty, Hank and their friends, "Snap" Collins, Crawford Cortland and Mildred Burnette, realize that Brock's gang is trying to keep Al from going straight. The boys follow Al, Tony and Dutch to a movie, and there Hank overhears a man with a German accent tell Al something about a one-eared dog in San Diego. Now worried, Hank, Snap and Crawford decide to go to San Diego to investigate, and Mildred discovers their plan and blackmails them into letting her come along. In San Diego, the kids get jobs that they hope will help them find the one-eared dog and learn more about Al's trouble. Mildred, who becomes a cigarette girl in a nightclub, finds a one-eared German shepherd and learns that it belongs to Henry Shrode, a German who frequents the club. Mildred tries to play up to Shrode, but the boys inadvertently interrupt her plan when they attack Shrode, thinking he is a kidnapper. The same night, Betty arrives, having figured out from Mildred's letters where they are. Later, Jimmie Collins, a bellboy at the same hotel that employs Hank, says that a guest named Shrode has him walk a one-eared dog every day. Hank takes over Jimmie's duties the next day and with Louie Schwartz, another new friend, goes to the Marine base with the dog. Hank hides while Louie approaches Al with the dog and tells him to go to the "place," then follow him to a barbershop. Returning the dog very late to the hotel, Hank is detained by Shrode, who is suspicious, but Crawford and Snap save Hank by sending a cat into the room to distract the dog, so that Hank can get away. Later, Hank goes to the barbershop and announces that he knows what is going on. Some of the henchmen torture him, but he is able to get away after pretending to faint. A few minutes later, with the help of Snap, he hides in the shop, then waits until everyone leaves. While there, he overhears Shrode and his boss Eric Kramer talking about a possible leak and revealing that Al had been framed for murder. Hank then follows Shrode to the telegraph office and, getting help from Crawford, who works there, reads the telegram, which asks Matt Herman to meet him at a San Diego steak house. The next night, Al and Betty are eating at the same restaurant when Herman, who is still alive, shows up. Now realizing that he has been duped, Al fights Herman, reports to his commanding officer, Col. Halliday, and reveals Brock's espionage activities. Because Al has not yet revealed any secrets, Halliday asks him to cooperate with the government. Kramer then summons Al, shows him that they are keeping Betty and Hank hostage, and demands that he acquire a "Mosquito" boat for the Germans. Al then goes to Halliday, who tells him to go ahead with the plan, and the Marines will take care of the rest. That night, Al goes to the Navy yard and steals the boat. Meanwhile, the kids go home and discover that Hank and Betty have been kidnapped and get the police to go to the barbarshop by throwing ink in Sergeant O'Hallihan's face so that he will chase them. At the shop, they find Kramer, who will not reveal where Betty and Hank are. The next morning, as Al approaches the freighter, Betty and Hank jump overboard. The Germans start shooting and mortally wound Al as the Marine planes fly by and attack the ship, which is bombed out of the water. Later, the kids are waiting to see Halliday, who gives them a reward. Halliday declares Al to be a fine Marine, then, at their request, lets the still underage Hank enlist. Finally, Mildred and Crawford get engaged.