The first time Zak Saturday met Ben Tennyson, they had to save the world from Dr. Animo and V.V. Argost together. It was an eventful day and the boys didn't have much time to really get to know each other. Still, they left with a photograph, so it wasn't a total loss.
They didn't speak for a while, assuming that it would be a one-time thing.

One day, Ben was called, saying that the Secret Scientists were coming into town to talk to the Plumbers. That was the second time they met. They talked. Ben told him more about aliens, which seemed to fascinate the young scientist. In return, Zak told Ben about his latest adventures with cryptids.
They exchanged phone numbers. Zak put Ben down in his contacts under 'Bigfoot', with a picture of Shocksquatch.

They called each other sometimes, when they could find time in their schedules. They talked about their respective lives. Zak explained cryptids to Ben, who just sort of made agreeing noises and seemed confused.
They made plans to hang out sometime.

The third time they met, it wasn't work-related. Zak came to Bellwood and they spent time together for real for the first time ever. His hair was in a ponytail and he was wearing normal clothing. Ben mentally noted that he looked pretty good.
They argued over whether to get milkshakes or smoothies and ended up getting soda instead.

They met up several times after that. They teased each other. They played video games and Zak beat Ben at Sumo Slammers while hanging upside down over the couch. They argued over television. They played stupid songs on the radio when no one was around.
They got comfortable.

The Gray Men got involved in a Plumber mission and Ben met Francis for the first time. They had petty arguments and Francis commented that the alien boy reminded him of Zak Saturday. Ben said he knew Zak and asked about Francis, who explained that they had a bit of a history.
Ben mentally noted to ask Zak more about his past.

Zak started becoming a regular sight around Plumber headquarters, his status as a Secret Scientist and connection to Ben granting him access. He got familiar with some of Ben's friends and family, including Max, Gwen, Kevin, and Lucy. Lucy seemed to trip in front of him and force him to catch her a lot.
Ben seemed slightly jealous.

One day, Ben remembered a half-forgotten phrase from their first meeting. He grew curious and, since he wanted to know more about the cryptid boy anyway, confronted Zak about it.
"What's Kur?"
"W-what do you mean?"
"When we first met. You called your cryptid power 'Kur power'. What does that mean?"
Zak grew visibly uncomfortable and started stammering out that it was something Ben really shouldn't know and it was all over now. He turned his back on the other and left, avoiding eye contact in the entire ordeal.
They didn't speak for a week.

Ben wondered if he should look into it or leave it alone. He really wanted to know, but Zak made it clear that wasn't a topic to be discussed. He wasn't even sure if he should apologize. One day, he got a knock on his front door and opened it to find Zak, holding a milkshake in one hand and a smoothie in the other. He handed the latter to Ben and offered to explain Kur. Ben said he didn't really need to, but Zak insisted. They sat down in Ben's living room and Zak told the entire story, start to finish. The tale was an emotional roller coaster that left them both exhausted.
Sandra found them asleep on the couch, Zak lying on top of Ben.

Their friendship seemed to strengthen. Zak seemed to behave slightly differently and the people around them started to notice. There were innocuous comments from co-workers and people asking if they had any plans. There were snickers when they decided to switch jackets for fun.
Lucy stopped flirting with Zak.

One day, Ben asked Zak if he noticed people acting weird about them. Zak's cheeks reddened and he said that, yes, he did notice and he knew why they did it. Ben asked why they did it. Zak tried to explain it, but Ben remained oblivious. Zak looked more and more frustrated, trying to figure out how to make the other boy understand, until instinct took over and he yanked Ben into a kiss.
It lasted about fifteen seconds and then Zak was turned around, not looking at Ben and apologizing profusely.
Ben stared.
Ben smiled.
Ben pulled Zak back around and back into a kiss.
It was a few minutes before they heard a cough and looked up to see Rook standing in the doorway.

"O-oh, um..." Ben started. "We were just..."
"Took you long enough," Rook interrupted. "Much longer and I would be losing money to Gwen. She made the bet for the longest amount of time before you two finally did something."
"There was... a betting pool," Zak said, flatly.
"It was Kevin's idea."
"... I'm gonna go kick Kevin. Ben, you coming?"
"Coming. Rook, you are not telling anyone about this, even to collect money."
"I do not have to. There were security cameras."
Zak just grumbled about beating someone up and continued his way down the hall, Ben on his heels and a smug Revonnahgander behind them.

They had a lot of explanations to get to.