Everyone knew that Bruce and Natasha had a thing.

Ever since the New York incident, they both had been acting very strangely. Both randomly disappearing with no explanation of where they went, both barely speaking to one another. There was obviously something up, and everyone else on the Helecarrier knew it.

Except for one problem: no one could prove anything.

Tony would try asking Bruce about it when they were working together in the laboratory. But he would always get the same answer:

"Tony, are you crazy? I'm pretty sure that you can guess that 'the other guy' makes any relationships a bit of an impossibility, least of all with Agent Romanoff. Plus I'm a scientist. I have work to attend to..."

And he would go back to adjusting the gravitational manipulator, or testing the atom accelerator, and leave Tony even less convinced of his crap than before he asked.

Meanwhile, Clint would try asking Natasha the very same thing during their training sessions in the Helecarrier's Combat Simulator Room. But he too would always get the same answer:

Usually a swift punch to the jaw, being told to shove off, and, depending on Natasha's mood, a snarky response about Clint's own bachelorhood.

Needless to say Clint let up with asking rather quickly.

And after a while, the rest of the Avengers also decided to accredit their suspicions to paranoia, and forget about it entirely.

And everything seemingly returned to normal after that.

But, little did the others know, that they were right about Bruce and Natasha. They had started a relationship together after what had happened in New York. And they both had grown to love each other very much, even if they would never say it.

They had kept it a secret because their love was different. Their love was something that no one else could ever understand, least of all their teammates.

Their love was measured not in passion, not in kisses, not in lust.

Their love was measured in moments. Pure, simple moments.

Like when they would sit in their favorite chairs reading; Bruce with his latest issue of Scientific Community, and Natasha with a Tom Clancy spy thriller, and gently clasp hands, never exchanging a word or a glance.

Or when she would have a nightmare and quietly make her way to his room, and he would hold her close until both would drift off to sleep in each other's arms.

Or when the others would take to New York City and party, and they would stay behind on the Helecarrier. Bruce would prepare a candlelight dinner and they would both eat together on the deck overlooking a starlight sea. Sometimes they wouldn't even speak. Sometimes they would just stare at each other.

And that was always enough for them.

Once they didn't even eat. They danced. Just danced together, slowly, lovingly, as the stars looked down on them. Bruce had no idea how to dance, and Natasha was very out of practice, but it never bothered either of them.

Because they were together. And that was all either would ever want or need.

And than, their teammates would come around, and they would always cover their tracks. Bruce would return to his lab, Natasha would return to her training, and everyone else would be none the wiser.

But they would always keep holding on to those moments. Those simple little moments together. And that's what would keep them going, no matter how bad things got.

But then one day, everything changed. Natasha and Clint were tasked with a two-year covert mission and Russia and had to leave immediately. She never got to say goodbye to Bruce.

And not long after that, Bruce left the Helecarrier, and return back to Calcutta to continue his medical work.

And that was that, so it would seem.

Tony would check up on Bruce every once in a while. Once he asked him if he ever missed Natasha. And he would always get the same answer:

"Yeah, I suppose. I sort of miss the whole team now and again. But my place is here, it's where I'm meant to be."

And, whenever they'd get a moment of peace, Clint would ask Natasha if she ever missed Bruce. And he too would always get the same answer:

Silence.

This carried on for six months.

Until one day, Natasha received a package. A simple, ordinary, brown package.

It was addressed from "Mr. Green".

At first, she thought the game was up and it was an enemy trick. She had no idea what it was or how a package would even get to her. But eventually, curiosity won over, and she opened it up.

Inside the package lay two objects. One was an ordinary looking CD.

The other was a simple white petaled flower. It was truly the most beautiful flower Natasha had ever seen.

But then she played the CD.

The first song on the CD was Glenn Miller. "Moonlight Serenade".

The very song Bruce and her had danced to so many nights ago.

That was the first night in a very, very long time that Natasha Romanoff, the Black Widow, cried.

Two weeks later in Calcutta, Bruce received a similar looking passage. Upon opening it, he found a single object inside.

A small crystal mirror.

"That's how I see you. That's how I've always seen you. Not as a monster. But as a good man."

Bruce turned around to find Natasha standing in the doorway of his shack. He was shocked. "Natasha? It's you! How did you find me?"

Natasha smiled. "I never lost you." she said, mimicking the very same words that she had told him when they had first met, so long ago.

Bruce approached Natasha. Neither had any idea of what to say.

So Natasha did what she had wanted to do for months. She ran toward Bruce, grabbed her arms around him, and they kissed for the very first time. It was long, deep, passionate, nothing like either could have ever imagined.

And when their lips finally parted, Bruce moved toward her ear and whispered a few simple words to her. A promise.

"I love you, Agent Romanoff."

She continued to embrace him, close her eyes, and whispered in turn to him.

"I love you too, Doctor Banner."

And, in that grimy shack in Calcutta, through a kiss and the exchange of a few words to each other, neither could argue that they had just made their greatest moment of all.