I REALLY want to do something like Summer Wars. If you've never seen it, here's a basic idea.

A program is implemented on the internet that makes it so everything you do is as easy as one two three and anything you can do in real life can be done in said program (martial arts, controlling anything electronic, casinos, shopping, chatting, anything). Our characters are schoolmates. Girl is from a well known family. Could be money, family's history, etc. Guy is a part time code monkey for the program. One day girl asks if he'd like an easy job but doesn't tell him it's to pretend to be her fiance. Her gram is old and it's her birthday so girl wants her to believe she's found love before she passes. But while there, the guy accidentally solves the supposedly impossible to solve encryption algorithm of the program, giving an AI hellbent in hacking everyone access. With access to anything controlled by the accounts it hacks, what's an AI to do?