The Pilgrims will head to Greenwich Avenue for a first-ever competitive meeting with Southern League Premier Central side Basford United (kick-off 3.00pm).
Basford are managed by former United favourite Mark Clifford, who has ex-Pilgrims Dominic Roma, Brad McGowan, Adam Chapman and Gregg Smith at his disposal.
The Pilgrims will be aiming to make it five wins from five under Ian Culverhouse, following their 4-0 victory at Lichfield City in the previous round and three successive National League North triumphs.
Defender Luke Shiels (hamstring) and striker Jordan Burrow (ankle) will definitely be missing from the United squad.
Should a replay be required, it will be staged at the Jakemans Community Stadium on Tuesday (kick-off 7.45pm).
LIVE COVERAGE
BBC Radio Lincolnshire full-match commentary, courtesy of Rob Makepeace and Craig Singleton, is available.
Twitter updates will be available via @bostonunited throughout the afternoon.
TICKETS
Away supporters can purchase tickets here.
KIT WATCH
United will be wearing their away kit of pink and grey.
PIC: Oliver Atkin.