Mirage gets a mysterious letter with no return address. His only human friend wants to know what's in the letter, which he doesn't find odd since they are both spies and work together. This letter could help a case they're working on until Mirage opens the letter. It turns out it's a secret the reader is revealing.

Mirage POV
(Y/N) and I have been working on a case for months. I think we're close to solving it. Today I decided we should take a break from our work. It's hard not to go into the office, but we've found a movie to watch.
"So, how about after the movie, we get back to work?" (Y/N) asks.
"We've worked too hard and don't know how to relax," I laugh, getting (her/him) to laugh.

(Y/N) POV
I asked Lennox to go along with my plan, and he should be giving Mirage a letter, or maybe he put it on Mirage's desk. I don't know why I'm in a rush. I could end up killing our friendship. I need to find something to distract myself. There's a training session for the rookies in the afternoon; maybe I can be a volunteer practice dummy or something.

Mirage POV
We killed a few hours watching the movie and getting lunch. (Y/N) left me in the cafeteria, saying they have something to do.

I'm about to go up to my room when Lennox hands me a letter with no return address and has 'highly sensitive information written in red. Add that it's addressed specifically to me. The universe doesn't want me to have a day off.

I don't want (Y/N) to know we might have something to help out the case. We're supposed to be taking a day off. I go invisible and go to my office. Even if this is only for my eyes, I'm certain it's related to the case.

Once the door is closed, I become visible and sit at my desk. I look at this letter, which aside from no return address, looks like a typical letter. Someone sent this and doesn't want us to know where they live. We'll take a look at this tomorrow morning.

I find (Y/N) helping Sideswipe and Ironhide teach the rookies. That'll keep (him/ her) busy until dinner. Now, what can I do for the day?

I end up doing a workout and attending an unexpected meeting with Lennox, Prime, and the new CIA director. Well, at least I don't have. to figure out what to do until dinner.

(Y/N) tells me she enjoyed helping with the training class, but (he/she) still wants to work on our case, even if it's only for three hours.
"No," I firmly tell ( her/him).
(Y/N) drops the subject — or I thought they did until I watch (him/ her) walking down the hall towards our office.

"You're ignoring this?" (He/she) asks, holding the letter.
"For the millionth time —."
"You're seriously not wondering what this is? A letter with no return address and saying for your eyes only? You really expect me to believe you can wait until tomorrow morning?"
(He/she) shoves the letter on my chest and walls out of the room, slamming the door behind ( him/ her).
Now (Y/N) has me wondering what this is. I sit at my desk and open the letter. Whoever wrote this wrote in pen.

Dear Mirage,
I know you are not thrilled to be working with humans, and I might be the only one you can tolerate. I knew working with you would be a challenge, but I quickly began to feel like we are meant to be together. I knew my feeling might change as we work together and get to know each other, but they grew stronger with each passing day. I've wanted to tell you, but knowing you're an alien who isn't fond of humans scares me. I know this letter can still ruin everything, but...

I love you, Mirage. Even while we work in frustrating cases, you make me happy. I'm glad you have come to wanting to spend time with me out of the office. I am afraid to even give you this letter, afraid I've ruined everything, but we are soldiers who take risks. Might as well take the risk.
(Y/N)

So that's why (Y/N) wanted me to read the letter. (He/she) wanted me to be in the office to get the letter. However, this way might have been better for them. They're not sitting at their desk, anxiously awaiting my response to the letter, unless...scrap.

(Y/N) POV
I'm trying to distract myself, watching T.V. in my room, but I can't keep myself from crying before Mirage even says anything about the letter. There's no way he likes me; a human.
I shouldn't have written the letter. Now working with Mirage is going to be awkward.

Twenty minutes pass before someone is knocking on the door.
"(Y/N)?" Mirage asks, concerned.
"Go away," I sob.
I forgot Mirage knows my access code, and he can let himself in.

Mirage POV
I feel bad (Y/N) is crying, even if it's the anxiety waiting for me to read the letter and what my reaction might be that's causing (him/her) to cry.
I sit on the bed next to (Y/N) and hug them. They wrap their arms around me and continue to cry.
"Hey, hey, it's ok, (Y/N)," I assure (him/ her), trying to get them to calm down so we can talk.

A few minutes pass before (Y/N) stops crying. I get a tissue and wipe (his/her) eyes.
"I see why you wanted me to read that strange letter. Good job acting."
This gets (Y/N) to smile, but I still see the worry in (his/her) eyes.
"It's ok, I read the letter and... I've felt the same way about you. I thought you'd think it's strange and alien loves you."
"Well, you thought wrong," (Y/N) smiles.
"You want to go out on a date now?"
"No, let's stay here and watch another movie, but we'll call it a date," (he/she) replies.

We go make popcorn and get some other snacks before returning to (Y/N)'s room.

We enjoy the movie, which turns into me sleeping with (Y/N), which I didn't think (he/ she) would have wanted to do this soon, but I'm happy to be with (him/her) longer than I thought I would have been.
"I love you, (Y/N),"
"I love you too, Mirage.'
I hold (Y/N) close as we fall asleep.