The 2011 version which is being made available on Hulu is a more anime-styled version, while the second and current reboot is the more comedic ThunderCats Roar.
While the reboot never quite reached the heights of the original, both series remain popular, and have since spawned a series of comic books and video games with the original show having since received two reboots courtesy of Cartoon Network. A small group, led by Lion-O, manage to escape the villain's clutches and seek out the Book of Omens which has the knowledge they need to defeat Mumm-Ra and bring peace to the planet. The kingdom is destroyed by an army led by the evil sorcerer Mumm-Ra, leaving the Thundercats enslaved. The 2011 Thundercats reboot sadly only ran for one season, and changes up the story a bit, with titular heroes living on Third Earth in the kingdom of Thundera. The Thundercats sudden arrival does not go unnoticed by the planet's hostile inhabitants, putting them on a collision course with demonic, mummified sorcerer known as Mumm-Ra.
When the Thundercats awaken from their suspended animation, the groups king and leader, Lion-O, discovers that his suspension capsule has slowed, rather than stopped, his aging, rendering him a child in the body of an adult. The series follows the adventures of the titular team of heroes, cat-like humanoid aliens, who are forced to abandon their dying home world and crash land on a planet called Third Earth. Created by the late Ted "Tobin" Wolf and produced by Rankin/Bass Animation Entertainment and Leisure Concepts, the original ThunderCats series aired its first run between Septemand September 29, 1989.