Sam and Lucifer are best friends. I mean it. They do everything together. They go and get coffee together everyday, they work in a call centre together, sometimes they go to the dentist with each other which is really weird but they do it anyway. They snuggle up on the couch together and watch crappy films, they go to concerts together. They do what most normal couples do with each other, apart from the kissing and stuff. If you didn't know them this would be perfectly fine, you would think they were going out, but they aren't. Their co-workers think it is really odd. They are just incredibly close.
Lucifer likes Sam and he wants to be his partner/boyfriend, or whatever but he doesn't think that Sam feels the same. He does though. Sam just won't do anything about it because Lucifer is incredibly good at hiding is feelings, even to his best friend.
One day after work Lucifer decides that he wants to go out for a drink. He drags Sam towards the nearest bus stop and they wait for a bus into the city. Sam doesn't want to go but Lucifer can make him go if he really begs, but today Lucifer doesn't need to beg, Sam will go anyway. It is Lucifer's birthday and he just really wants to go out for a drink. They arrive in the city twenty minutes later, Sam still complaining. They walk into the first club they see.
Lucifer goes to the bar and orders a beer for Sam and a vodka and coke for himself. They find a table to sit at and they drink their drinks, really quickly. Sam goes to get the next round and he comes back with a V&C and beer, but also two shots of this incredibly alcoholic odd tasting green stuff. He tells Lucifer it is half price so they get a couple every time they get more drinks. After their fourth round Lucifer grabs Sam's hand and pulls him up to the dance floor, insisting that since they are at a club they need to dance. Sam can't dance. He doesn't go to clubs and he hates the music playing. But he is incredibly drunk and it is his best friends birthday, he can't leave Lucifer to make a fool of himself alone, it is his duty as a friend to join him in embarrassing themselves. They dance to a host of songs Sam despises and they get a few looks from some of the other club goers. They drink several more of the green shots and dance a lot throughout the night.
At half past midnight they are chucked out the club for being too rowdy. Sam is sad because he really enjoyed dancing with his best friend and even though he knows they were being too rowdy Lucifer is still shouting at the security guard. Sam grabs his hand, apologises to the guy at the door and pulls Lucifer down the road, in the direction of the park.
They sit on the swings in silence, looking at the stars for ages, neither one wanting to break the silence, but Lucifer can't stand the silence. He stands up and pulls Sam up with him. Lucifer drags Sam around past the pond, still holding his hand. Sam looks down, he likes this. He really likes holding his best friends hand.
Lucifer stops suddenly. He drops Sam's hand but quickly grabs the other one. Lucifer turns to face Sam. He slowly lifts his hand to Sam's neck and pulls it down, so they are level. Sam blinks and Lucifer pulls him closer. The next moment they are kissing. For at least twenty minutes they go between a state of staring at each other and kissing each other, then Lucifer breaks the contact. Sam winces and goes in for another kiss, only to be pushed back. Lucifer looks at Sam, with tears in his eyes. He tells Sam the one thing he has been dreading over the past two weeks. "Sam, I'm leaving." Sam stares at him and asks why. Lucifer tells him that it is because his mother has died and he needs to look after his younger brothers but Sam doesn't take it well. After a lot of crying and shouting (about how you can't kiss someone like that then tell them your leaving, especially your best friend) Sam turns and leaves. He doesn't look back.
Lucifer is standing in the dark beside the pond, crying. The most heartbreaking thing is that he doesn't think Sam will ever talk to him again.