Pang Saneh Ha (The Lost Soul)

When Techit (Thanapol Nimtaisuk), an honest young police officer, is suspended from duty and targeted by Denis (Asadawut Luangsuntorn), a mafia drug lord, he goes into hiding at the farm of his close friend, Sri-Trang (Thikamporn Ritta-apinan). It is here that he meets "Siang-Waan," an amnesiac female ghost. Techit helps Siang-Waan uncover the truth about her past, and their close proximity blossoms into a deep bond.
When Techit discovers that Siang-Waan is actually Plai-Dao (Pechaya Wattanamontree), Denis's sister-in-law, and that she already has a fiancé named Paul (Kant Kantathavorn), an Interpol officer, he is heartbroken but still determined to help her return to her physical body. No one knows that Paul only got engaged to Plai-Dao to gain Denis's trust, which would make it easier to gather evidence against his illegal business operations.
Meanwhile, Paul is actually "P'Petch," Sri-Trang's ex-lover who left her without revealing that he did so for her own safety. Because of this, Sri-Trang holds a grudge and is hostile towards Paul every time they meet.
Techit successfully helps Plai-Dao return to her body, but she wakes up with no memory of him. Techit is forced to put his feelings aside for the time being and teams up with Paul to successfully take down Denis. Afterwards, Paul reconciles with Sri-Trang, and together they help trigger Plai-Dao's memories. Eventually, Plai-Dao remembers Techit and the love she has for him, bringing happiness back to everyone once again.