This position paper describes the implementation and initial findings of a game called Personal Investigator (PI). PI is an online 3D detective game that implements a model of Brief Solution Focused Therapy (BSFT). It aims to help teenagers overcome mental health problems and engage with traditional mental health care services. It is predicted that the combination of goal-oriented gaming with a model of goal-oriented therapy will help to attract and sustain the interest of teenagers, a group that therapists often have difficulty engaging with. PI is the first game to integrate this established psychotherapy approach into an engaging online 3D game.