Takes place at the ruins of The Alamo.
First of two episodes dealing with Time Travel. In both cases, characters travel from Thundarr's era back to 'Ancient Earth" (i.e. our modern time) in order to bring something (or someone) back to the future.
The evil wizard's name in this episode is Crom. This is a connection with another famous barbarian. In the saga of Conan the Barbarian, Crom is the name of the god that Conan prays to.