Pyaar Kii Ye Ek Kahaani S08 E07 Dipanita and Arnab's plan fail

"Can a vampire and a human ever be together?"

Abhay takes Piya's locket, which unveils a werewolf's true identity. Dipanita and Arnab's plan fail as Chand eats the sweet which Arnab had brought for him. Why is Arnab shocked?