Beastmaster 2: Through the Portal of Time

Dar, the son of a king, is hunted by a priest after his birth and grows up in another family. When he becomes a grown man, his new father is murdered by savages and he discovers that he has the ability to communicate with animals, which leads him on a quest for revenge against his father's killers.

The Beastmaster Dar is forced to travel to earth to stop his evil brother from stealing an atomic bomb, and turning their native land from a desert into... well... a desert!

Before he died, Dar's father gave a mysterious amulet to Tal, Dar's younger brother who is now king. Dar, while wandering with his animal companions, chances to meet and rescue a family who seek the help of King Tal against Lord Agon, a sorcerer who has conquered their land. Dar obtains an audience for them with Tal, who rallies his troops to march against Agon in the morning. Alas, the young king is captured by Agon's crimson warriors during the night.