It takes place after Twilight forgives Trixie for what she did in the episode "Magic Duel", and Spike doesn't buy it. Twilight learns from her friends how Spike really feels for her and now she has to fix it.
Spike has had it. It's not his fault the library is a shambles. But he's not gonna take the blame. Until Twilight starts appreciating him, he goes on strike.
A rewrite of a few Season 1, Season 2, and Season 3 episodes I felt could've been done differently. (WARNING: the rewrite choices are my personal opinion)