You will find a boy crying just outside of the Poké Mart in Kevlar Town. When you first visit, he tells you to just leave him alone, but if you revisit the town after receiving HM04 (Strength) from Kellyn in Legen Town, he'll finally decide to ask you for help. The Dunsparce Gang, a local biker gang has stolen something from him and run off to the Passage Cave Grott-Hole, a small cave located to the far west of Kevlar Town.