Tony Stark and Bruce Banner bonded after they both joined the Avengers. Neither of them had really liked the idea in the beginning, but they liked each other, and decided they wouldn't have a problem working together.
Given that Bruce was a scientist and Tony was a genius when it came to technology, they spent a lot of time working with each other. They were two different personalities, and sometimes clashed over ideas, but they mostly worked well together, and quickly became good friends.
When they first met, Bruce had thought Tony seemed like an arrogant jerk, and Tony had a hard time looking past the fact that Bruce turned into a giant green monster whenever he was angry. But eventually, they both looked past all of that, and realized there was a good person underneath, in both of them.
After a while, they started to get a lot more fond of each other than originally were. Each one developed a bit of a crush on the other. Bruce didn't think much of it at first, but one day a conversation with Tony made him think otherwise.
"So, Banner," said Tony, "There anyone special in your life? You know, romance and stuff?"
He said in a very casual way, but something about it made it seem strange to Bruce.
"Uh, no," he answered. "I don't think so."
"Right." Tony nodded. "Mm-hmm. Just wondering."
Something about it didn't sit well with Bruce, and it made him start to wonder if Tony reciprocated that feeling he had, which made him begin to reevaluate his own feelings.
Things were awkward between the two men for a few days after that. And then one day Tony suddenly said, "I think we should spend some more time together. You know, outside of the tower and work and everything. Gets kind of stuffy in here, you know?"
Bruce nodded and said, "Yeah. Okay, that...sounds nice."
Tony and Bruce began to become something more than friends after that. They kept it to themselves, and no one thought there was anything romantic between them. They didn't know why, but they liked having their own secret, one that just theirs and didn't have anything to do with the rest of the team.
But their secret started to come out when the team was out on a mission, and Bruce had had to turn into the Hulk. Once the mission was over, Natasha was going to get Banner back to himself, but Tony said, "No, wait. Let me."
Tony walked slowly over to the Hulk and said, "Hey, big guy. The sun's getting real low."
He held out his hand and began to whistle softly. The Hulk responded to it, and soon enough the Hulk disappeared and Bruce sat on the ground next to Tony.
"Wow. You're good," he said.
Tony smiled. "I know, right?"
"Well, I think the secret might be getting out now," Bruce pointed out.
"Ah, who cares anymore? That's old news already."
They both smiled. Everyone else was probably staring at them, but right then, nothing else really mattered to them besides each other.

YOU ARE READING
Multi-Fandom Imagines
FanfictionA series of imagines from different fandoms. Disclaimer: I do not own any of the characters in this book. All rights go to their respective creators.