Donald Woods as Captain Bob Dayton

Kathryn Adams as Mary Blake

Robert Armstrong as Lieutenant Ed Carey

Eduardo Ciannelli as Felix Lynx

Jacqueline Dalya as Innis Clair

Billy Halop as Tim Bryant

Reed Hadley as Caddens

Irving Mitchell as R.S. Hinchfield

Edgar Edwards as Henchman Teal [Chs. 3-6]

John Holland as Henchman Hess

Roy Gordon as Maj. Gen. Fletcher [Chs. 1-2, 4, 11-12]

Alex Callam as Capt. Long [Chs. 1-2, 4, 11-12]

Phil Warren as Bakeman [Ch. 4] (as Philip Warren)

Bill Cody Jr. as Jack Hurd