in the hollow of (one's) hand
Under one's total influence, domination, or control. Often used in the blessing "May God hold/keep you in the hollow of His hand." At this point in history, these four men held the entirety of Europe in the hollow of their hands. She now has the entire company in the hollow of her hand. We are all sending our thoughts and prayers to you and your family during this tragic time. May God hold you in the hollow of his hand.
in the hollow of your hand
entirely in your power.