The Elusive Mr. Smith: The Secret Billionaire Society Book 7
Nancy Pennick

Everyone wants to know … who is Mr. Smith? As the six friends gather for their thirty-first birthday celebration, they are no closer to the truth. Smith did not return their money as promised and has the nerve to call with another mission. After hearing the details, the men swing into action. This time the assignment is personal. One they'll never quit until everyone is safe.
**The Elusive Mr. Smith is best read after reading one of the first six books.