It ambushes you with actual mythology in the time it takes to boil a kettle. Hakone is a hot spring spirit whose centuries-long nap left her stuck in the body of a little girl, and the show plays that for jokes without ever forgetting she's a genuine deity trying to claw her power back. Touya is the perfect straight man: a high schooler who wandered into an onsen and walked out on divine payroll, and his exasperation is the engine of every punchline. The real flex is how much spirit-world lore gets smuggled into three-minute chunks, enough that you start taking the rules seriously in a series designed to be background noise. It drifts in the middle stretch, no argument, a few episodes wander off looking for a point. But it stays warm, and warm is the whole job here. Watch it the way you'd sit in the water: no rush, steam on the face, nowhere else to be.
Hakone is a hot spring spirit who wakes up at a resort after centuries of sleep, trapped in the body of a small child despite her ancient age. When Touya, a high school student, discovers her naked and confused in the bathhouse, he gets dragged into her mission to recover the spiritual powers she's lost during her long dormancy. What starts as an awkward first meeting becomes an unlikely partnership as Touya helps Hakone navigate the modern world and reconnect with her supernatural heritage. She's impulsive and childlike in the most literal sense, while he's stuck playing the responsible adult in their dynamic. Together they encounter other spirits, tackle bizarre situations at the resort, and slowly rebuild what made Hakone powerful in the first place. The comedy comes from culture shock, slapstick moments, and the constant tension between Hakone's ancient wisdom and her toddler-sized body. It's lighthearted supernatural slice-of-life that doesn't take itself seriously, perfect for when you want something funny and charming without heavy stakes or complicated drama.