3x01 Emma & Hook #1 

In the season premiere episode, "Heart of the Truest Believer," as Emma, Mary Margaret, David, Regina, Mr. Gold and Hook enter Neverland to search for a kidnapped Henry, they're greeted by a school of not-to-friendly mermaids who threaten to end their search before it begins; Henry finds himself on the run from the Lost Boys with another escapee from Peter Pan's encampment; and Neal, recovering from his wounds, travels through the Enchanted Forest with Mulan in an attempt to learn the fates of Emma and Henry, on "Once Upon a Time," SUNDAY, SEPTEMBER 29 (8:00-9:00 p.m., ET) on the ABC Television Network.