Otonari no Tenshi-sama ni Itsunomanika Dame Ningen ni Sareteita Ken

Synopsis

One rainy day, Amane sees popular classmate Mahiru sitting on a swing and offers her his umbrella. The next day Mahiru notices Amane caught a cold from the rain. Amane returns to his apartment where he lives alone and finds Mahiru with his umbrella as she actually lives alone in the apartment next to his. As his cold had become worse, she supports him inside his messy apartment and cooks porridge for him. After getting better, Amane learns that Mahiru is an excellent cook and hates the nickname Angel that everyone calls her at school. They both agree to act as strangers at school but the next day Mahiru realised Amane lives on take-out food and energy drinks so she offers to make dinner. This soon becomes a routine of cooking for him every night. Amane's friend Itsuki actually notices Amane looking healthier from his improved diet. Mahiru finds Amane actually trying to clean his apartment and decides to help, after which Amane buys pizza. Mahiru reveals she has never had pizza as her parents are rich enough to employ a chef, leaving Amane confused why she struggles living alone on a budget. He asks why she is bothering to cook for him and she insists it is the satisfaction of showing off her skills, but Amane is unconvinced.

(Source: Wikipedia)