Panthro gets insecure when he finds out Barbastella has a history of dating royalty, so he tries to impress her by becoming "King of the Machines" and giving all the appliances in the Cats' Lair artificial intelligence.

Lion-O's dad King Claudus arrives on Third Earth… and turns out to be a big selfish jerk! Now Lion-O has to deal with his dad before he goes to war with the rest of the ThunderCats.