Air date: Mumm-Ra is weak and he faces the threat of three new ThunderCats, so he sends the Mutants to release his old enemies the Lunatacs imprisoned in Dark Side in order to bolster the forces of evil. The ThunderCats celebration of their victory over Mumm-Ra and the welcoming of three new ThunderCats is cut short when Snarf overhears plans at Castle Plundarr after he chased Ma-Mutt there from the Berbil village.

Mumm-Ra Lives – Pt. 2

The Mutants succeed in releasing the Lunatacs. The ThunderCats discover their Thundrylium mine is being looted and people are being kidnapped from the villages. Lion-O and the ThunderKittens have their first run-in with a Lunatac and Bengali's skills as a blacksmith come in handy.

Mumma-Ra Lives – Pt. 3

The ThunderCats build the Tower of Omens to monitor for Sky Tomb which will be run by the new ThunderCats. Ma-Mutt disguised as a Berbil spies on the ThunderCats plans and the Lunatacs are sent to destroy the Tower. Snarfer contacts Snarf to tell his uncle that he's coming to Third Earth.

Mumma-Ra Lives – Pt. 4

Mumm-Ra's power is restored. Snarfer makes it to Third Earth but crashes in Dark Side and the ThunderCats rush to his aid before the Lunatacs can get ahold of him.

Mumma-Ra Lives – Pt. 5

The ThunderCats look for Sky Tomb to free the slaves imprisoned inside it. Bengali must learn the importance of teamwork as Lion-O leaves him with guard duty. Lynx-O and Cheetarah run reconnaissance to find out if Mumm-Ra is truly back or not.