There is an interview that answers that question: http://www.tvguide.com/News/Once-Upon-Time-Bosses-1044444.aspx
The last we saw of Snow White in the fairytale world, she had erased her own memories. When will you pick up that story again?
Kitsis: [This Sunday's episode] takes place right after the Huntsman released her, so before she's attained all her banditry skills. In fact, there's a scene you'll see, where Red (Meghan Ory) teaches her how to track. Episode 16 [picks] up directly after the episode where she drank the poison.
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"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy