"Chemistry, because that's exactly what you and I have," Smackle beamed up at Farkle at their lab table, finally pleased to be in a challenging class. On the opposite side of the room, Zay and Riley shared a look.

"Now don't start expecting me to be that sweet to you. I'm nice and all, but that kind of sweetness just aint normal." Zay shook his head at the two of them, clearly a little grossed out by their PDA but still playful.

"Oh come on, Zay. They like each other. They're just excited to spend time together." They turned to look as Smackle and Farkle giggled, spelling out compliments with the periodic table.

Even if they were a tad cheesy, seeing Smackle and Farkle together always warmed Riley's hear a little. They seemed so perfect for each other, like two sides of a coin. It made her wonder about what would happen if she were to really be together with someone so much like her. She pushed this thought away quickly. This wasn't the time to think about Lucas. Just at the mention of his name all these moments would flash through her mind. Tombstone. Something happening between him and Maya. Stepping back. Farkle revealing her feelings. The three of them on New Years…all of it one huge mess, and nowhere to turn. But still, looking at how happy Smackle and Farkle seemed to be…what if the universe really wanted them together?

"Okay, I'm starting to see your point," Riley said, turning away from the pair. "but they are cute. Do they make you miss a certain someone, Zay?" Riley scrunched her face into a fish-lipped kiss. "Va-ness-a?"

Zay pushed her back. "For your information, I do happen to miss her, but it's got nothing to do with those adorable weirdos."

"Whatever you say, Zay." Riley twirled a piece of hair around her finger, blowing a few more kisses to really seal the deal.

"Right back at ya, cotton candy face."

"What's that supposed to mean?"

"It's supposed to mean I know you've got something going on in that pretty little head of yours."

"Oh, really?" Riley raised an eyebrow, sarcastic.

"Look, I'm no expert, but if you're trying to hide it, you're not doing so great of a job. It's like uh…like a phase change, right?" Zay picked up one of the ice cubes from their beaker and dropped it onto the hot plate. "You started out as a solid, but now you're turning into a liquid. You can't help but change, and even when you try to hide it, we can all start to see you melting." The ice cube transformed into a puddle, and Riley felt her stomach drop. "Whatever's on your mind, Riley, don't let it get the best of you, okay?"

Riley watched the puddle begin to disappear from the plate, gripping the beaker a little tighter in her hands. She wouldn't disappear. She couldn't. Things weren't going to fall apart.

"Looks like you two make a pretty good team!"

Riley dropped the beaker with a loud squeak. "Farkle! You scared me. Oh gosh, watch out for the glass." She stepped back, taking his arm with her.

Zay sighed, still smiling. "You stay out of the way, clumsy girl. I'll grab the broom."

"Sorry about that, Riley. I didn't mean to scare you," Farkle said.

"Oh no, it's fine. I was just lost in my head for a second," Riley stared off towards the window, still not quite back to earth. Farkle eyed her curiously.

"I guess not all partners can be a perfect team," he ventured.

"Right, we all can't be you and Smackle."

"Oh, I was actually talking about us."

"Us?" And just like that, Riley was grounded again. Farkle was pleased to have her full attention.

"Well yeah. I thought we did pretty well last year, making history and all. It's kind of a shame to have to change things up so quickly."

"But isn't this a good change? Don't you want to work with Smackle?" Riley looked back toward their station, where Smackle was still reading over a notebook.

"Of course I do," Farkle beamed. "but working with Smackle is different. It's more of a friendly competition. A loving rivalry. And as much as I enjoy it, that doesn't mean I won't miss being your partner. But Zay's probably gaining on me right now."

Zay slid past them, dancing the broom across the floor. "You don't wanna compete with all this, man." He called back. "You got the brains, but I got the moves."

"He's right." Farkle broke out into a poor robot move. "I don't have that kind of skill."

"But you do have quite a lot of charm," Smackle added, coming to his side. "Our lab prep is looking excellent, thanks to improvements by yours truly. His calculation were way off."

"See what I mean?" Farkle said, sending a wink Riley's way. "Always ready to outshine me." He wrapped an arm around Smackle's waist as the bell rang. "Let's head out to celebrate your genius."

Riley fell in line behind them, eyes on the two of them intertwined. Is that what the world had planned for her, sometime soon? Is that what would cause the eruption?