The Ipswich loanee scored from close range three minutes after the break at Home Park on Saturday, after Barnet's defenders had charged down two shots on the six-yard box.
The visitors had taken the lead against the run of play in the 21st minute after player-head coach Edgar Davids swept a pass out to the left and Elliot Johnson's cross back into the penalty area was converted by Bees top scorer Jake Hyde.
Argyle continued to press and were rewarded when skipper Conor Hourihane scored a brilliant 36th-minute leveller, beating three players on the edge of the box before letting fly with a superb rising drive into the top corner.
In a nervous finish for both relegation-haunted sides, Argyle's Jake Cole made a vital 79th-minute point-blank stop to deny his former club. The keeper's save at the foot of his post denied Bees substitute Iffy Allen, who looked odds-on to score.
Bees keeper Graham Stack then made a superb close-range save to deny Argyle substitute Gozie Ugwu in stoppage time.