Flame Princess is on the warpath, Finn's got the hots for her, and you just know this can't end well. Jake's unleashed trouble by bringing her to the treehouse, and only he seems to realize it.
"No, really man, her Dad said she was evil!"
"Nah, man. I peeped beyond her burning gaze and noshed hot lunch with her soul. She ain't evil. She's passionate."
Any relationship that can be had between Finn and Flame Princess would be tempestuous at best (hell, even FP knows they can't be together). Action-wise, 'Hot to the Touch' has a rampaging fire monster and the Goblin Kingdom under threat (saddle up the fireproof mechs, baby!), but in the end, this is all about teenage heartbreak. And hormones. Lots of those.
It's pretty heavy stuff, but at least we see signs of Finn mending his soul. At least for now.
8/10