Fuyu is exhausted from the unrelenting criticism and the unreasonable workload from his boss... 
Until one day, when he runs into Ito, his ex-girlfriend from college.
 
Fuyu is so happy to see Ito that he immediately invites her out for a drink, and they talked about their old days and new lives.
Just as he was thinking that this is a nice kind of friendship, they stumble into a one-night stand...
 
(Source: Ura Sunday, translated)

Yamase Fuyu, tired of his black job, runs into Ito, his ex-girlfriend from college, one day and invites her out for a drink. They talk about their old days and their new complaints, and just as he was thinking that this is a nice kind of friendship, they get carried away by the energy of alcohol and end up having a one-night stand. Fuyu regrets what he did, but Ito tells him, "Don't apologize. Don't say, 'Let's get it right.'" Ito, too, was tired of being forced by society to always act properly and adult-like. Thus, the two form a mysterious relationship where they only do fun things, without worrying about work, love, or other troublesome annoyances.
 
(Source: Shogakukan, translated)

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