The Mauch Twins return in this fast-paced adventure, the third and final film in the Penrod series, loosely based on the stories by Pulitzer Prize-winning author Booth Tarkington (Alice Adams). Penrod Schofield (Billy Mauch) is missing! Convinced he's been kidnapped, his parents post a $5000 reward for any information leading to their boy's return. So when a carnival huckster named Professor Caligostro brings Penrod home to his folks, they never suspect it's really Danny Dugan (Bobby Mauch), a runaway orphan who's the spitting image of their son. With the real Penrod held prisoner by Caligostro's gang, it's up to the guilt-ridden Danny to rally the neighborhood boys into finding Penrod before the reward is collected and the Professor escapes!