Hmmm I don't know. Perhaps you don't meet some of the requirements? Or you can click on the question mark in the upper right corner of the screen to see the instructions
(I unlocked the vent event. First, I had to tap on the vent when I saw the glowing eye inside, then talk to Molly, Jenny, and Amy about how to unlock vent. Wait until night and then I got the key from the black box in the refrigerator)
Try it again.