Eunsu is not happy that his mother’s new boyfriend has sons—a pair of twins at that. What was his mother thinking leaving out that important bit of information?! And when his mother tells him she might just marry the man, Eunsu is dead against it. But Eunsu’s trouble ensues when the twins are more than determined to win their new ‘hyung’ over and lend him a helping hand to change his mind. Will Eunsu give in and be bound to them in more-than-familial ties, or will he stay steadfast in his decision?