REBORN! Season 1 Episode 16 Escape from Death Mountain!

Dino takes Gokudera and Yamamoto to an unexplored area where Tsuna is supposed to be receiving special training from Reborn, but meet up with Tsuna, who had gotten lost, along the way. As the four teenagers come face-to-face with numerous dangerous obstacles, it becomes clear that someone has planted traps for them. Then Reborn appears to tell Tsuna that the place they're visiting is built exactly like Death Mountain, a secret Vongola training ground that has a survival rate of one in a hundred!