A loyal German Shepherd dog follows his master to the French front in World War One.
| Actor | Role |
|---|---|
 Thunder the DogThunder | Thunder |
 George HackathorneBob Henley | Bob Henley |
 Marjorie DawMary Blake | Mary Blake |
 Mary CarrMrs. Henley | Mrs. Henley |
 Will WallingWilliam Marshall | William Marshall |
 Brooks BenedictJack Fenton | Jack Fenton |
| FFlash the DogFlash, Son of Thunder | Flash, Son of Thunder |