When they reached Death’s kingdom , the stakes shifted. Death wasn't a monster to be slain, but a fundamental force. He didn't want their lives; he wanted to see if they understood the gravity of their quest.
Death, moved by the sincerity of a boy trying to fix a small broken thing in a vast, dying universe, allowed the flower’s soul to return. [S2E17] Death in Bloom
The episode (Adventure Time, Season 2, Episode 17) follows Finn and Jake as they accidentally kill Princess Bubblegum's prized plant and must journey to the Land of the Dead to retrieve its soul. When they reached Death’s kingdom , the stakes shifted