Attack of the Faceless People

The princess Serena of the Sun People arrives on Amzot, being pursued by Darkon of the Faceless People. Darkon wants Serena so he can control her people. The Herculoids successfully drive him off, but not before he captures Tara. Zandor agrees to a trade, but substitutes a berobed Gleep for Serena and they destroy Darkon's palace from the inside.