All they had intended to do was look inside. The doorway had stood in the alley for as long as anyone could remember, a strange blue wooden door that looked wildly out of place in the gray brick of the building it was attached to.
The building it was attached to was an old tenement house. Alex had lived in the building for all of his life, and he knew that the door didn't connect to the boiler room that was on the other side of the wall. He'd peeked through the door for the first time when he was six; it had been a dare from Rosa, the daughter of a neighbor who was the same age as Alex.
That first time, the door had opened up to a long hallway made of old-looking stone with flaming torches lining the walls. It was a smooth marble entryway with seven passages leading away when he had turned the dare back upon Rosa. After that, daring each other to look in the door had been a game, with the rewards and punishments for chickening out gradually going higher and higher until they'd been thirteen, and he'd dared her to look in and describe the room or kiss him.
Rosa had described the room, a queer-looking place of metal and glass, before turning around to his slightly disappointed face and pulling him into a kiss. In the end, nobody was terribly surprised by the games they had played turning into a courtship ritual aside from them.
And through it all, they kept peeking in the door; never anything more. Their parents had never commented on the door, but some gnosis had warned them from going any further; much like the much commented warnings of caution from their parents had on their physical affections. Three years of first love, companionship, and the tender dance in each had been enough to appease both their wants and their parents.
Though as their romantic dance grew closer, the dares become more bold; one of them standing inside the room while the other stands at the door holding it. They had long ago set a pebble inside the blue door, and the room's shifting took the pebble with it.
It wasn't until they approached their seventeenth year that they saw a room that looked anything like one they had seen before. Alex had been dared to stand in the room for a full minute while Rosa held the door. Rosa had gasped when she opened the door, proclaiming that the room looked so much like the first room she had ever seen.
Something in that change had spurred Alex to search a little farther in his minute, poking his head down each hall. He heard Rosa calling him, saying it had been quite long enough, please come back. But something held him, some fascination in the patterns of the marble that Alex only shook when he heard the sound behind him of wooden shoes on stone.
He whirled, seeing Rosa walk towards him, a cross expression on his face.
Behind her, the blue door slammed itself shut and faded into a discolored patch of stone.