Aria - Season 2 Episode 13 Those Really Self-Imposed Rules...
Overview: Alice has created a new challenge for herself: when she walks home from school, she can only step on shadows. This is an ironclad law for her - but try as she might, she keeps failing. Even worse, Athena interferes by trying to help out. Alice's self-imposed challenge is something that she must conquer alone, or so she thinks; but maybe there's more to success than just doing everything by yourself.