After finishing high school, all five of them choose a different but anime-related path. The series focusses on Aoi Miyamori, who starts working as a Production Assistant at a middle-tier anime studio that has managed to land a big project. Through her work, we get to see all the steps of the production of anime. from scenario to storyboards, keyframes, color etcetera.
(And most of the works seems to be juggling schedules and begging the animators to work a bit harder to make up for a slipping schedule earlier in the chain. It felt a bit familiar...)
The real stars of the series are the characters. There's a big cast (making anime takes a lot of people!), but all of them have their own mannerisms and personality -- which keeps things really interesting. I liked two secondary characters the best: Honda-san, the Project Manager of the first series, who goes on to follow his dream. And Yuka Okitsu, the administrative lady who has several unsuspected tricks up her sleeve.
If you liked Bakuman, then you will love Shirobako. It's a refreshing look at a (dramatised) anime studio trying to deliver a great series.