ThunderCats - Season 1 - Eps 1: Omens (1)
Lion-O, always outdone by his adoptive older brother Tygra, undergoes the ritual to be chosen by the Sword of Omens as the next king of Thundera. His father, Claudus, does not feel his son is ready because he is too lenient and easily distracted by flights of fancy like the myth of ancient technology. Soon after, King Claudus welcomes the return of his friend Grune and holds a celebration in both his honor and in memory of the fallen Panthro. During the event, Lion-O defends a pair of captured Lizards and convinces his father to release them.
About ThunderCats

Title: ThunderCats
First Air Date: 2011-07-29
Last Air Date: 2012-06-16
Status: Ended
Rating: 7.9/10 (from 238 votes)
Language: EN
Seasons: 2
Total Episodes: 26
Network: Cartoon Network
Genres: Animation, Sci-Fi & Fantasy, Action & Adventure
Production Companies: Warner Bros. Animation, STUDIO4℃
Synopsis
The ThunderCats are on the move! After the kingdom of Thundera is attacked by the lizard people, Lion-O leads Tygra, Cheetara and the other heroes on a quest for the Book of Omens and the magic stones of legend. But he'll have to face villains like Mumm-Ra, the ancient evil sorceror, and Slithe, the dangerous lizard general. Luckily, he has the Sword of Omens and its amazing powers at his disposal.