Jack and Tooth found themselves in a strange corridor full of windows with a diamond shape.
"I don't remember seeing this when I saw my memories" Jack said confused as he look around himself.
"That's because I'm here with you. When I see the memories with someone else, this corridor appears so the child can show me the memory he or she wants me to see right away" Tooth explained.
"Well… that makes sense" he said.
"Um… Jack? You can let go of my hand. We are not going to disappear if you… you know… let it go" Tooth said, blushing a bit as she said that.
"Oh. Sorry… I didn't realize I was still holding it" Jack said while he also blushed.
"So… where's the memory you wanted to show me?" she shyly asked.
"I guess it must be at the end…" Jack said as he walked towards the end of the corridor. Tooth followed him stopping a bit to see the past Jack from time to time. She smiled when she saw the memory of the snowball fight against the town bully; giggled when she saw him give his sister a scare with a worm; got a bit angry when she saw him give a blond girl a blue flower…
"You had a girlfriend?" she asked, trying to hide her jealously.
"Yeah, but it didn't work out. She cheated on me the week after we started dating" he answered. Tooth let of a little breath of relief. Jack gave her a funny look.
"Oh… sorry about that" Tooth said with embarrassment.
"Don't worry; now that I think of it… I really don't know what I saw on her. She was really selfish" Jack assured her with a smile.
The smile, however, faded when the two got to the end of the hallway. The window showed a smiling Jack with a pair of ice skates leaned in his right shoulder.
"We´re here" he said with a grim look on his face.
Tooth touched the window, and after a little flash, the two Guardians were standing in the scene.
Jack was just walking out of his house, his sister pulling his left arm in excitement.
"Be careful" Ms. Overland said. Jack turned to face her.
"We will" he said with a laugh and a grin on his face. His mother smiled and closed the door.
"So, sis, race you to the lake?" Jack said to his sister. She smiled and started to run, Jack soon following laughing.
"Aww, your sister is adorable" Tooth said. Jack sadly smiled as they followed his past self and his sister.
"Yeah… it was hard not to like her" he said.
The two Overland siblings arrived at the frozen lake. Jack found an abandoned shepherds staff…
"Isn't that your staff"? Tooth asked. Jack nodded.
…and touched the frozen lake surface to be sure the ice was thick enough. He then proceeded to help his sister put on her skates. After that, he walked in the frozen surface by her side as she skated a bit.
"Wait here so I can put mine now, all right?" he said. She nodded.
But before he could put his ice skates on, Jack heard a cracking sound. Turning his head to where the sound came from, he saw to his horror that his sister was standing in thin ice… and so did he.
"Oh my…" Tooth gasped horrified.
Putting his skates down, Jack tried to put a calm face. He needed to get his sister out of there.
"It's okay- it's okay… don't look down… just… look at me" he said, mentally kicking himself for appearing nervous. If he showed her he was nervous, she would panic.
"Jack, I'm scared" his sister said as the ice kept cracking under her feat.
"I- I know- I know" the cracking noise wasn't really helping.
Suddenly, an idea started to form in his mind.
"But you are going to be all right. You're not gonna to fall in. Huh… We're gonna have a little fun instead" Jack said with a reassuring smile.
"Jack… that's the same thing you said to Jamie when Pitch had cornered us 3 years ago" Tooth said as she looked at him. He huffed.
"Yeah… that's when I realized that my center was fun" Jack said, looking at his past self with a little smile.
"No! We're not!" Jack´s sister said with a scared voice.
"Would I trick you?" Jack asked as his eyes fell on the abandoned shepherd's staff.
"Yes! You always play tricks!" his sister replied.
"We-well… all right well- well not- not- not this time. I promise… I promise you're gonna be… you're gonna be fine" his sister looked at him.
"You have to believe in me" he said.
Tooth's heart sank. Jack said that… and then he had to spend 300 years in a world where no one believed in Jack Frost.
His sister let out a breath and nodded.
"You wanna play a game? We are gonna play hopscotch! Like we play every day" Jack said with excitement. His sister just smiled.
"It- it's as easy as- huh- one…"he put a foot on another spot, where the ice also cracked. He frowned. That wasn't helping.
"Wow!" he said pretending to lose his balance as he looked at his sister. She laughed.
"Two…" he put another feet in a different spot, the one he knew the ice was thick.
"Three!" Jack said with a smile as he jumped towards the staff. He ducked to pick the wooden object. He never took his eyes off his sister.
"All right" he said as he grabbed the staff.
"Now is your turn" he said as he put the staff in front of him, the curved part pointing at his sister.
"One…" Jack´s sister gave a small step, a gasped escaping her mouth as the ice kept cracking.
"That's it, that's it… Two…" Jack assured her as he clutched the staff. The ice was still cracking, and his sister was beginning to panic. It was now or never.
"Three!"With the help of the staff, Jack grabbed her around the waist, therefore pulling her forward into the thick and safe ice.
Unfortunately, when he pulled her, he landed on the exact same spot his sister had been earlier. None of them took notice, because the two siblings were laughing out of relief.
Not for long.
Tooth let out a breath she didn't realize she was holding.
"You saved her" she said as she looked at Jack with a smile. Jack´s face darkened. Tooth then noticed where the Past Jack was standing.
"Oh no…" she said.
Just when he stands up to join his little sis, the ice broke… taking Jack to the bottom of the frozen lake.
"JACK!" his sister screamed.
Jack tried to swim back to the surface, but the cold dragged him to his doom. Then, the moon started to glow and Jack´s lifeless body began to rise. As it got closer to the surface, Jack´s brown hair turned white; his fair skin turned pale; and when he opened his eyes, instead of brown they were a bright blue.
Jack and Tooth then got blinded by a golden light again, and when they opened their eyes they were back in the real world.