Lego Ninjago: Masters Of Spinjitzu: Season 0, Episode 5

0 - 5: Return to the Fire Temple

Kai and Nya are taken back to the Fire Temple by the fire dragon, named Flame. At first thinking he was homesick, the dragon shows another entrance to the Underworld, hidden within the temple's catacombs. The Skeletons try to get out and Kai attacks.