A high school student suddenly taken into the world of Weiss Survive, a typical kind of card game.   He&#039;s weak against big boobed and moe girls, but the one who can turn him on the most is his childhood friend, a real tsundere.   

Takeshi was just an ordinary guy until a perfectly innocent study session with Michi - the most beautiful girl in the school - ended up with him being mysteriously transported into the strange dimension known as the Weiss Schwarz Battle Space. Once there, a crazy but enthusiastic old man informs him that he is the chosen warrior and must win a succession of card battles to get back home. 
The only problem: he doesn't know how to play! However, with the expert Michi ready to teach him the ins and outs of this bizarre and improbably slapstick card game, Takeshi will learn the ropes and get ready for the card battle of a lifetime. Assuming he survives the training...
 
(Source: Anime News Network)

Wei&szlig; Survive card game manga. 
The story follows the main characters Takeshi and Michi as they get lost in the Card Battle world and have to win card battles to return home.