It's another Arthur's underwear.... Follow the main story and/or all affinity available and it will be done... Sorry don't remember exactly =/

It's something about Horace's story/affinity !! <3

Something beautiful, something good =p

If I remember correctly, you'll need to get Affinity with Horace. I don't remember which, but you'll get a cutscene with Arthur and Horace, trying to get a key from him. After that, you'll be able to purchase the underwear from the Bandit! Hope that helped! :3

Hmm. I already did that, but #23 is still locked. Am I supposed to buy it from the Bandit or something?

Hi, where can I find the 28th underwear? Ive trying to unlock it for 3 days now