1
general::
In preparation, under development. For example, The agent said there was a movie deal in the works, or He assured her that a follow-up campaign was in the works. [Second half of 1900s] Also see IN THE PIPELINE.
American Heritage Idioms
2
general::
Phrase(s): in the works
Fig. being prepared; being planned; being done. • There are some new laws in the works that will affect all of us. • I have some ideas in the works that you might be interested in.
McGrawhill's American Idioms And Phrasal Verbs