in charge

in charge  {adv.} or  {adj. phr.},

1. In authority or control; in a position to care for or supervise; responsible.

If you have any questions, ask the boss. He's in charge.

2. Under care or supervision.

The sick man was taken in charge by the doctor.

During your visit to the library, you will be in the librarian's charge.

Compare: TAKE CARE OF.