The series involved a 'spy' of some kind infiltrating a secret base where everyone was made into adult babies. The pictures were of a pretty ABDL girl who was in the kitchen and was pretending to be one of the babies, but one of the 'masters' already knew she was a spy. She gives her a bottle and forces her to drink the mind regression drug turning her into one of the babies she was in there to save.
Hopefully someone remember this caption, if I had to guess, it would have been from around 5 years ago. Thanks for your help!