Hoppy, California and Johnny come to the ranch of a friend and his daughter, disguised as dude detectives from the east, to investigate the disappearances, without a trace, of several herds of cattle.

William Boyd
as Hopalong Cassidy

Andy Clyde
as California Carlson

Brad King
as Johnny Nelson

Wanda McKay
as Lucy Brent

Jack Rockwell
as Jim Brent

Norman Willis
as Kervy

Jimmy Wakely
as Lead Guitarist Cowhand

Johnny Bond
as Second Guitar Cowhand

Dick Reinhart
as Mandolin Cowhand

Robert Kent
as Henchman Drake