Dungeons & Dragons (1983)

Season 1: Episode 4

The kids come to the aid of a unicorn named Silvermane, the leader of the last unicorn herd, who under attack by wolves. But when their attention is diverted, an old wizard named Kelek kidnaps Uni. The kids seek out the evil man, who is trying to steal all the horns from unicorns to harness the teleportation powers they possess. But they find themselves too late to save Uni, who is now weak and hornless. The kids free all the de-horned unicorns and ask to be taken to the Valley of the Unicorns so they can protect the remaining three from the Kelek. But little do they know that they are leading someone else into the valley with them.