"Plunkett" continued such duty until joining Task Force 39 (TF 39) on 20 March 1942. Six days later she departed the east coast for Scapa Flow and arrived in Orkney on 4 April to commence operations with the British Home Fleet. Employed on North Sea patrols and escort work over the first leg of the Murmansk run, she was relieved, by , in mid-May and assigned to escort the battleship back to the United States. Coastwise and Caribbean escort duty followed and in August she returned to the North Atlantic to accompany UK-bound convoys. On 2 November, she departed New York On her first escort run to North Africa. Delayed en route to allow time for the clearance of wreckage from her port of destination, her group delivered its charges with their reinforcement troops and equipment to Casablanca on the 18th. Then, after patrolling off the Moroccan coast she returned to New York and local operations off southern New England.