Mako Storm is an agent with the CIA.
Make that a contract agent. That is a key point. He and his partners have to vie with other operatives for the lucrative contracts and when a mission does not go as well as hoped, the partnership's name drops down a few pegs in the pecking order and the times get lean.
Storm's partners are wife and husband team Alicia and T.J., put that way because it is pretty obvious the one in charge is Alicia. They run their operations from their dive boat where they maintain a cover as diving guides. It is an occupation and a pasttime that all three enjoy a great deal but operating such a boat is expensive and without the added funds coming from their CIA missions, the payments would be impossible to make. This gives added pressure to get the job done and done well, besides the standard one of Storm, being the primary field agent, getting himself seriously dead.
Storm is a dedicated operative who never lets anything interfere with the mission - or so he would love it to be believed. In truth, he is a good agent and has a good track record but he does love a nip or three and a pretty woman can and does distract him on far too many instances. In modern parlance, he is a 'playa' and how that has not gotten him killed so far is amazing.
Also complicating his life is his ongoing rivalry with his father, John, who also is a contract agent and sometimes works with the three and sometimes seems to compete with them. John Storm is a very, very experience operative and gets irked with his son's attitudes. Mako Storm in turn gets frustrated at being in the shadow of his father and shows it. When the two of them are together, it is hardly a Hallmark moment.