Mit mir nicht, du Knallkopp

Long-time student Harry's dog Wurstl is shot by a hunter and then escapes through the Saale river to East Germany. There he is picked up by the agent Charlotte. She is supposed to track down two agents lost in Munich and bring them back to health. Using the address in Wurstl's collar, she finds the two students Harry and Charly, who help her in her search. Charly suddenly meets the twin brother of Charlotte's superior in the restaurant where he works and recognizes in him the rampant hunter who had shot Wurstl with a homemade rifle that shoots around corners. Apparently Charlotte's boss wants to get hold of the wonder weapon...