wait but what if the pink girl is actually not mute and chengxiao is somehow connected to her? ok idk. OR maybe the reason why the pink girl gave the photos to Lu cuz she actually wants him and chengxiao to go back into the future and find her brother? And she knew that only cheng can go back into the past so that's why she specifically wants to meet chengxiao and maybe tell her what clues they've got from going back into the past omg i dont know