While Satoru was "betting time" asleep in his coma, what became of the lives his childhood friends lived without him? This special extra volume of Erased checks in on the lives of Satoru's friends and the bonds they wove thanks to the chances at life his "revival" gave them.
Awesome Cherry on top
It kinda did feel like I needed more of a resolution when the main story ended. I definitely got that here with this volume. This author knows how to express the lengths these characters are willing to go.