It's based around Vincent, the guy in my theme, who's in a long-term (5+ years) relationship with a woman (named Katherine) who wants to get married and he's unsure whether he's ready for that. Then one night another woman named Catherine (the girl in my signature) comes up to him in a bar and hits on him, and they spend the night together and he begins to cheat on Katherine with Catherine. Meanwhile, every night when he sleeps he has terrible nightmares where he has to climb a tower made of blocks that he pushes and pulls to make a staircase up.
The game is similar in play to the Persona series if you've played them. During the day you make decisions on what to say to Katherine and Catherine, who to talk to, and other things such as that that will make you lean towards one girl or the other, and at night it's a timed puzzle game where you climb to the top and out-climb bosses that represent Vincent's various fears.
Sorry that was long-winded but it's my favorite game so I want to explain it REALLY well XD;