The first season was mostly stand alone eps after the first couple, thou it had a multi part story where Lion'o has to beat the other Thundercats in various trials, before facing his most powerful enemy, without the Sword of Omens, due to the rules and that meant taking on Mummra himself, on his own! Season 2 starts off with what was the movie, spilt up into five parts and from that point onwards, the series has a tighter storyline and the Thundercats also get new enemies, thou also new friends members of the Thundercats themselves! Come to think of it, only once that I can recall, in the whole series, did the Thundercats come to complete defeat and imprisonment for eternty, by a carefully laid plan by Mummra and the Mutants, yet they overlooked the seventh member, Snarf! The new enemies for a time were quite a considerable threat to the Thundercats, thou evenly in one ep, Lion'o outwits each of them, through various means, of course, Mummra remained the primary villian because out of all the 80s villians, he is pretty much the embodiement of Evil and being ever living, means, he immortal, thou he has retrictions upon him and is kind of a slave to the anicent sprits of Evil and their will, thou they take a bit more of a active role from season 2 onwards!