Michael Spillane's 67th-minute strike from the left was turned in on its way to goal with Bees striker Charlie MacDonald claiming the final touch.
The Bees went ahead in the 26th minute through midfielder Marcus Bean, who followed up at the far post after Romain Larrieu had brilliantly saved Spillane's header.
Argyle drew level in the 38th minute when Rory Fallon headed the ball in the air and spectacularly volleyed home following an angled cross from Onismor Bhasera.
In an exciting four minutes of stoppage time, Larrieu made a brilliant save to deny Bees dangerman MacDonald.
The ball was cleared downfield by Argyle winger Craig Noone and Bees keeper Richard Lee made an equally fine save to deny Argyle substitute Rory Patterson.
Source: PA
Source: PA