"I've only just met her today... so what's wrong with me? Why am I feeling this excited?!" Narumi is a high-spec, popular man who has gotten bored with life since everything goes his way. On the other side is Takanashi, a woman who passionately throws herself into her hobbies and work. People call her "the tuna that'd die if she stopped swimming." Through a twist of fate, these two people who are polar opposites had a marriage interview with each other. Narumi attended the meeting with the intention to reject the other party. However, an attacker rushed at him during the interview, and Takanashi handled the situation with extremely magnificent martial arts?! Takanashi, who Narumi looked down on as a straight-laced oddball, is actually "Taka-san," a mysterious person Narumi has extremely high regard for! Receiving a shock, Narumi had already embraced her by the time he noticed... A mismatched, cute, and extremely lewd "First love x First love" comedy!