The White Mage had used her magic, whiteout, and brainwashed nearly all of the Fairy Tail Guild. One of those brainwashed was Cana, or so everyone had thought but was actually just extremely drunk. The White Mage had ordered all of the brainwashed guild to go and wreak havoc.

Cana: While the other brainwashed members of Fairy Tail wreaked havoc on Magnolia, Cana was stumbling through the streets with a large bottle of ale in her hand that she was drinking Ah~... That's so good… she mumbles as she takes another swig, oblivious to everything that was happening; even oblivious to the fact that she was wearing nothing but a white cloak and was barefoot