Drenched in Dog-Blood Drama: Who Swapped Me into the Lead Role?

[Cross-dressing as a man + transmigrate into a book + System + school life + long-laid plans + substitute romance] [Cool, ascetic top student × lively, cheerful mission-taker] Ye Wanxing had always worked diligently for the Main God. Then, in one stroke, she transmigrated into a book with a System, disguised herself as a man, and set out to protect the male and female leads’ beautiful but doomed love story. But before the story even got underway, the male lead came to stay at her house, and her identity as a girl was exposed. H-How was she supposed to play this now? What a scare! Luckily, the System told her she just had to make sure the male lead didn’t die. But why was he always hanging around her? Had someone secretly switched the protagonist on her? Later on, the heroine fakes her death to escape the Main God’s control, and the male lead makes her his substitute. (He has already recognized her.) Our little Xingxing can only say: This is ridiculously melodramatic! Who switched my protagonist?