As the heir to a sword immortal, Bu Chen'ge once single-handedly held back a calamity from the demon realm. But a romantic scandal and political intrigue stripped him of his immortal status and cast him down to the mortal world, where he became a homeless man anyone could bully.
Tang Xin, a modern girl, transmigrates into this xianxia drama as an invisible "ghost" by his side. Without a body and unable to touch anything, she can only quietly accompany this fallen hero and witness his suffering.
The vicious Mo Yu places a love curse on Bu Chen'ge, making him fall obsessively in love with Fanxing, a scheming female disciple from his sect. He gives her everything, only to be met with contempt and exploitation. Tang Xin's heart aches, but without Bu Chen'ge knowing, she takes on some of the heart-devouring pain caused by the curse. At a crucial moment, she even sacrifices her chance to block a fatal blow meant for him.
An old sword immortal takes Bu Chen'ge to an ancient temple to undergo rigorous training and temper his sword heart. Meanwhile, the girl's soul meets Wanlian, a medium who can sense her, and the two become confidantes across the boundary between life and death.
When the medium's life reaches its end, she gives her body to this soul with nowhere else to turn. Returning to life in another body at last means Tang Xin is no longer a nonexistent bystander. She reunites with Bu Chen'ge, and the truth behind their story and its many mysteries is finally revealed.
Mo Yu realizes that she is actually deeply in love with Bu Chen'ge and takes a blow from the Demon King meant for him. At last, Bu Chen'ge fully awakens and begins to face the responsibility he bears, setting out to save the immortal realm once more.
Theme: True love is selfless. It only wishes for the other person to be well.
