Mumm-Ra summons the Berserkers and coats their armor with Thundrainium and sends them to attack the Thundercats at the Tower of Omens. Realizing that their armor is coated with Thundrainium, the Thundercats at the tower need help and Lion-O and Tygra rescue them. They create a windstorm to rub off the Thundrainium and the Berserkers retreat. Meanwhile the Lunataks invade Cats' Lair and the Thundercats must rush back to save the Thunderkittens and Snarf who are being held as the Lunataks' slaves.