Juvenile delinquent Jun'ichi rescues pretty Yuuhi from two troublemakers. The next day, she shows up in his class, where he attempts an awkward kiss. Things get more awkward when Yuuhi appears at Jun'ichi's house later ... as his surprise fiance!
After learning the details of their arranged marriage, Jun'ichi and Yuuhi are having a weird time adjusting to living together, and Yuuhi may just spend spend her first night sleeping on the couch.
After Jun'ichi's teacher disappears, the student council president sends Jun'ichi and his friends to investigate-in a creepy old part of the school. But when Jun'ichi and Yuuhi fall through a trap door into a pit, they're suddenly way too close for comfort.
Jun-ichii is dragged along to a classmates house party with Minato, but when they arrive, they are embarrassed to learn it's actually a formal event on a huge cruise ship! After switching into borrowed clothes, Jun'ichi is suddenly creeped out by Minato's revealing dress.
Jun'ichi is in hot water after inviting Minato to watch a movie with him, and neglecting to to invite Yuuhi, so Minato fakes a phone call, forcing Jun'ichi and Yuuhi into a date. The next day, the date is the talk of the school.
Jun'ichi and his friends visit a mountain resort, and Karen takes the group on a long hike to the Ayanokouji family's secret hot spring?which they soon find out is a co-ed bath.
It's the school Cultural Festival and Yuuhi, Karen, Fuyuhiko and Tsukasa (along with the rest of their classmates) are doing a Yakisoba café. However, they face tough competition from the Yakisoba stand put up by Minato and the tennis club.
When the students are given a career investigation assignment, Tsukasa sets out to fulfill her dream of becoming a voice actress by preparing for an audition. But on the day of the audition, she loses her voice!
Minato convinces Yuuhi to help with Jun'ich's surprise birthday party by getting Jun'ichi's present, but Yuuhi has a difficult time choosing a gift. Minato offers to let Yuuhi bake the cake instead as her present to Jun'ichi.
Yuuhi fakes being sick so Jun'ichi will stay home from school to care for her. That's when she demands a redo first kiss. Everything seems ready to fall into place, until Minato takes the chance to drop a bombshell announcement.
Yuuhi meets with her father and rejects her engagement to Jun'ichi, saying she'd rather decide for herself without external pressures. Upon her return Yuuhi senses some weirdness she can't place in the Nagase home, but neither Minato nor Jun'ichi are willing to admit anything.
After Jun'ichi came back home after meeting his parents, Yuuhi was so angry over Jun'ichi lying to her that she decided to break up with him and leave the house that night. The next day, Minato left the house as well in order for Jun'ichi to make a decision between her and Yuuhi.
For summer break, Jun'ichi and the group head to one of Ayanokouji's family's privately owned islands. But, the school president has a secret plan to make this vacation as, um, interesting as possible.