Sano and Miyata, two childhood friends, are on a trip together in a resort hotel facing the Pacific Ocean. Miyata is devoted to conspiracy theories and he tries to get Sano to believe this idea. But Sano doesn't believe it, and they fight. As Miyata's phone keeps ringing all day, Sano loses patience and takes the call. It was a phone call from Miyata's father, who was saying unintelligible things, probably from dementia. Sano hangs up the phone in confusion and tries to go home with Miyata.

Accompanied by his friend Miyata, Sano returns to Izu, a seaside resort in Japan where five years before he fell in love with his wife Nagi.

「ぼくらのへんたい」などで注目を集める漫画家ふみふみこのコミックを、東京藝術大学大学院映像研究科映画専攻の学生たちが実写映画化したオムニバス作品。身体からトゲが出る特異体質の女子高生の葛藤を描く「いばらのばら」、ある秘密を抱える夫婦の奇妙な日常をつづった「豆腐の家」、恋人への未練をひきずる幽霊が巻き起こす騒動を描いた表題作「恋につきもの」の3作品で構成。「恋につきもの」では原作者ふみふみこと制作スタッフが原案を共同開発し、それぞれコミック化、映画化するという試みがなされた。出演は「絶叫学級」の松本花奈、「カナリア」の石田法嗣ほか。

Snow covered mountains in Japan. Every night, a fisherman makes his way to the market in town.
His 6 year old son is awoken by his departure and finds it impossible to fall back to sleep. In the sleeping household, the young boy draws a picture he then slips into his satchel. On his way to school, still drowsy, he strays off the path and wanders into the snow...

December 30th, 2017. Two years before the Tokyo Olympics, due to a revision of the Constitution, a National Defense Force is created in Japan and it starts military operations. In an incineration plant, a dog goes lost, but when Tani goes looking for him, she finds nothing. In the plant, Yanais takes down the Christmas decorations and replaces them with the ones for New Year. Gou, addicted to survival games, comes to the plant during the night and starts playing video games with Ken, even if it is his day off. In the meantime, Adachi is just watching their game to kill time. However, all these men share similar problems: pregnancy, adultery, family issues and a friend who died in the war. Meanwhile, Tani, who is troubled with her immoral relationship with Adachi, begins to feel that her father, who was the plant’s manager and is supposed to be dead, seems to be around somehow.