On a cattle drive Hoppy, camp cook Windy, companion Lucky, and young Artie Peters encounter an eccentric professor. The professor professes to be searching for the evolutionary missing link, but in reality he is a cattle rustler who uses his dynamite to scatter the cattle in order capture some of them. Hoppy and Bar 20 guys ultimately capture the professor.
William Boyd
George 'Gabby' Hayes
Russell Hayden
Nora Lane
Harry Worth
Lois Wilde
Billy King
William Duncan
Jack Rutherford
Ernie Adams
John Beach
Ben Corbett
Frank Ellis
Leo J. McMahon
Artie Ortego
Blackjack Ward