A girl (15 years old) goes to her new school and discovers that the dorm she was supposed to be staying in is under renovation and she has nowhere to stay. After some begging, the school admin gives her the key to an apartment, which she later discovers is where the Chairman (aged 16 yrs!) stays...
As some have already commented, the guy looks like he's around 20 and the girl looks pubescent. The story is quite basic shojo fare and I think if you have read enough shojo you would know what to expect to happen from page one onwards. The guy, despite his cold tsundere look, is actually pretty decent to her. She, on the other hand, is somewhat ditzy but still bearable. She is also supposed to be rather smart, where studies are concerned.
The storyline is a bit confusing at the end where new elements are added in a rush. There are some bits of other plot concerning the guy's competition as Chairman of the school.
The mom is rather silly though IMHO. Actually, her words of encouragement for them to "get it on" were a bit of a put off to me. I mean, she was like meeting that guy for the first time and there was no guarantee he would take any responsibility.
Spoiler (highlight to read)
Also think it would have been nicer if she had actually been proposed to, rather than have the guy tell the whole world that they were getting married without even asking her first.
Recommended? Suspend disbelief and just enjoy the art and some sweet moments between the two.