The whirlwind of the Mad Hatter's hat was stronger than anything Emma had ever felt before. She saw Regina falling in and no matter her feelings toward the cruel woman, she wasn't just about to let her fall to some godforsaken Wonderland or anything. So, she grabbed onto her and pulled her out, causing herself to fall in. Mary Margaret, not willing to let her daughter go jumped in after and the purple tornado engulfed both.

When Emma finally opened her eyes after the nauseating trip, all she was neon lights tracing a room. She got a good look around and to her immense surprise, she was wearing some kind of a suit and helmet, with blue circuitry on it. She recognized it immediately as the suits from the 1982 Tron movie and couldn't help saying: "Oh man, this isn't happening, it only thinks it's happening." Next to her, she saw Mary Margaret. "Mary Margaret! Mary Margaret, are you okay?!" Snow woke up to that and saw her daughter, wearing a very eccentric-looking helmet on her head. "Emma? What are you wearing?" Emma couldn't help but chuckle slightly. Out of all the worlds she could've ended up in, she ended up in Tronville.

Suddenly, several blue-lined programs appeared with discs in hand.
Funny, these guys were always red in the movies.
"Identify yourselves!"
Emma, being cautious chose to say: "I'm Emma and this is Mary. We're... we're actuarial programs and uh... do you know Tron? We're looking for him."
The security programs stiffened slightly.
"Commander Tron is busy in the other sectors of the system. Identify your purpose."
"We need Tron 'cause he has experience with Users. We... thought he could help us with something. Please?"
The security programs looked disbelieving but then the leader said: "We'll contact him. Take them to a holding cell."

The security programs escorted Snow and Emma to a holding cell somewhat similar to the one that programmer guy, Ram and Tron had been kept in. As soon as they got there, Emma quickly explained everything she remembered of this realm and they both agreed not to reveal their identities to anyone but Tron. Soon, the security programs returned, more relaxed.
"One of you can now contact Commander Tron." they said. Emma left the cell with them and followed them to a blue version of Sark's command ship where she was allowed to step into his little "MCP tube" where a holographic Tron appeared.
"Who are you?"
"My name is Emma, I'm a User and I need your help."
Tron squinted his eyes.
"Go on."
"My friend and I, we got trapped. We need to find a way back home, we're from another world.
Tron restrained rolling his eyes. The situation was so depressingly familiar. He tried not to think of Flynn these days. The User had been his friend but as soon as he got his Grid, he'd copied himself his own Tron and left with him to build his precious digital frontier.
He said: "Look, believe it or not, I'm not exactly an expert on how this traveling between the worlds works, but one thing I can tell you is that getting out is a lot harder than getting in."
Hadn't Flynn used some kind of an I/O portal in Tron: Legacy?
"What about the I/O portals?"
Tron scoffed. "They're only capable of communication. If there's someone you can talk to in the User world, then..."
Suddenly, Emma got an idea. "Storybrooke!"
Tron was confused. "What?
"We're from Storybrooke, does that exist here?"
"Where is Storybrooke located, I have a world map program who could help."
Emma continued, excited: "Storybrooke's in Maine, do you think he could find it?"
"We can try."

Tron walked to the bridge and ordered the pilot programs to set course back to the heart of the ENCOM system. Thoughts and memories filled his brain. His adventures with Flynn, Ram and Yori... taking down the MCP... Flynn leaving for the last time with the other Tron...
But despite his painful experience, he never forgot his main directive:
I fight for the Users.