In the snowfields of Snezhnaya, a small snowman called a Jack Frost has been swiping clothes from bathers at a hot spring near Central Station. Catching the thief hands you back the stolen clothes and opens a Precious Chest, but the snowman moves too fast to grab by hand. The trick is to trap it with a construct instead of chasing it.
Quick answer: Place a Grappling Gun near the fleeing Thief Jack Frost behind the hot spring building, let the hook pull it in, then return the recovered clothes to the person hiding in the barrel to spawn the Precious Chest.
Where the hot spring is
The hot spring sits in the southwestern part of Central Station. While exploring that area, you will reach a pool with a cluster of barrels tucked into a corner. Approaching the barrels triggers a Shrill Voice calling out for help.
The person inside the barrel took a dip in the hot spring and had their clothes stolen by a thief. They are cold and embarrassed, and they ask you to get the clothes back. That request starts the chase.
How to catch the Thief Jack Frost
The person in the barrel turns out to be the owner of the hot spring. As an apology for the theft, they force the Thief Jack Frost to work for them.
Rewards for catching the thief
Completing the interaction spawns a Precious Chest. It contains a set of buttons you can trade, which line up with the Intricately Patterned Buttons used at Jack Frost Village’s shop to buy items and decorations.
You know it worked when the owner steps out of the barrel and the Precious Chest appears. Three additional common chests also show up at the spot where the owner was trapped, so sweep the area before you leave.
Bonus: unlock the Koski, Options achievement
The same hot spring holds a second puzzle that grants an achievement. Head south-west and speak with Kintutu, a traveler from Natlan. Her Flowfire Bird companion, Javita, keeps running back and forth through the warm water and will not settle.
To stop the bird, build a cube in the gap in the fence. The block seals the opening the bird runs through, which halts its loop.
Once the bird is stopped, Kintutu thanks you and disappears. That confirmation unlocks the Koski, Options achievement. Three common chests also appear in the area, giving you extra loot for solving the problem.
With the thief caught and the bird settled, both problems at the hot spring are done, and you walk away with a Precious Chest, several common chests, and the Koski, Options achievement.
