Boy loves girl, girl loves violent lying DQN, DQN needs money for his little sister (a lie), girl wants boy's 200,000 yen savings to giie to DQN, boy request sex, girl agrees, girl talks about DQN and how good he is, girl starts yankee-fication, sex becomes more focused with boy until she actively cheats with boy. Eventually DQN's lie is exposed and they break up. Girl still date other guys but has sex with boy although not quite sex-friends.
Thank you, that was a good summary. I have one problem though. I tried to look up the meaning of DQN, and came up with several different pages saying contradictory things. The Japanese Wikipedia page for DQN (filtered through a horrible machine translation) seemed to say it was a violent Yank, or something. Urban Dictionary says it's an abbreviation for dokyuun, a sound of a heart beating. Another page says it means dumbass. Yet another says it stands for an Amtrak station in Illinois. Can I get some clarity on this? Much obliged.