Go to 3-2 "Pipework" and unlock 3-H1. Go directly down from 3-H1 and you will find it. (if you unlock it it will show you a path to the level)
SPY mouse is the all-new, bite-sized adventure from the creators of Flight Control and Real Racing. Agent Squeak is SPY mouse, an undercover operative secretly serving the needs of mice everywhere. Embark on a journey of epic proportions, over two years in the making! Can the world's smallest hero prevail in one of iPhone's biggest games? His fate's in your hands!