This achievement requires that you complete the orb game in the Blue Grotto without losing a single node to an orange sphere. The Blue Grotto is towards the very end of Episode 5. The object of the game is to guide a ball of energy from one point to another across the screen, connecting all points. Your enemy will be orange spheres, which if they hit you connection from point to point while you are moving, it will get destroyed. There is three rounds and they get harder as you progress. The key is that there is no time limit. Just take your time and go slow, never taking a risk to get your energy to the next node. The good news is, if at any point you actually do get hit by an orange sphere, you can hit the "Restart" button in the top right corner to reset the round with no penalty. Just make sure you are quick to avoid the background auto saves. This should not be a problem however. There is no real solution for this one. With a little experimentation, timing, and patience, this achievement will be yours.