Like an average cliche, there is no party that happens without any sort of drama.
Jia Hao could already guessed Wu Mengji bribing a person to secretly take the necklace and frame Su Yunqi. It was probably she who spilled the drink on Su Yunqi's clothes.
As Su Yunqi was cleaning her clothes in the washroom, the girl secretly placed the necklace in Su Yunqi's purse.
Like a perfect female protagonist, Su Yunqi totally didn't notice the changes in her purse, not she open it once again for any reason.
' If everything happened normally, the necklace would have been found in Su Yunqi's purse.'
' Even though many wouldn't have believed Su Yunqi was the thief, her reputation probably going to get stained.'
' After all, once a gossip starts, it spreads like wildfire. Wu Mengji would have used the chance to fan the flames and make Su Yunqi go even lower.'
' Tsk, Who is writing such plots? Even I can write better than it.'