The ThunderCats take refuge on Third Earth, where they are strangers in a strange land.
The broad strokes of the ThunderCats story tell an epic tale that is both familiar and fresh.
In order to survive and free Third Earth from Mumm-Ra, Lion-O, the childlike leader of the ThunderCats, must learn responsibility and how to be a leader.
These kind of story elements are familiar to audiences and have been proven to work in other properties, so they can work here.