What? My Soulmate Betrayed me!

The Crown Prince of the Great Yan had a family wiped out and let another man be blamed for it. Mei Lin, a killer raised by the Dark Factory, is the daughter who survived. The token she carries names Murong Jinghe as the man responsible, so she crosses into the Great Yan to kill him. The attempt goes wrong. She and Murong Jinghe end up carrying the Twin Breath Poison, a paired worm that ties the two of them to one life, so neither can die without the other. In the time they are forced to spend together she works out that it was the Crown Prince who destroyed her family, and the two of them agree to take revenge on him together. They come through several situations that could have killed them both, and feeling grows between them. Then Murong Jinghe's fiancée, Muye Luomei, sets a trap that shows Mei Lin she has been a piece on his board from the start.