The Town slipped to an injury-time defeat to league leaders Plymouth as Ryan Brunt’s 95th-minute winner gave the league leaders Argyle all three points.
Josh McQuoid had earlier netted his first Town goal, nodding into an unguarded net to equalise with just 14 minutes left to play.
It had looked as if Luton would push on for all three points, but Ryan Hall’s sending off gave the impetus back to Argyle, who eventually nicked the winner.
The visitors had earlier led through Carl McHugh, but the Hatters conceded their fifth last-minute goal in League 2 this season to ensure Plymouth returned to Home Park with the points.
Pelly Ruddock-Mpanzu was given his first league start for almost a year among three changes from John Still, who also brought in Luke Guttridge and Nathan Doyle from Tuesday’s draw at home to Leyton Orient.
The Hatters, missing Craig Mackail-Smith due to injury, opted to play one up front, and the style almost paid immediate dividends when Guttridge fed in Jack Marriott but the striker was unable to gather with less than a minute on the clock.
The home side had the better of a frenetic first 10 minutes, although Plymouth weren’t without chances as Gregg Wylde nodded wide from a left-sided Craig Tanner cross.
Tanner proved the proverbial thorn for the Hatters in the first half, and it was he who played a major part in opening the scoring after just 15 minutes.
The winger received a short corner on the edge of the box, whipping in an in-swinging delivery which McHugh nodded past Mark Tyler to send the large away support into pandemonium.
It was all Argyle from there on, with Tanner once again getting sight of goal but finding the gloves of Tyler, who was worked far too hard in the first half from a Town perspective.
The Hatters got a foothold just after the half-hour mark, although an early change was required when Alex Lawless replaced the injured Dan Potts, forcing Sean Long to be switched to left-back in just his second Town game.
That change prompted some Hatters chances on goal, first from Guttridge, firing a curler from 30 yards into the hands of Luke McCormick, before Marriott had a cross-shot from ten yards blocked by the Plymouth stopper.
Yet Argyle remained a threat. Twinkle-toe dribbling from Graham Carey saw him wriggle through three Town players in the area, but his shot was dealt with once again by Tyler.
The half came close to ending even worse for the hosts as captain Scott Cuthbert was being seen to by seven medical staff following a collision with Tanner, but the stalwart was able to carry on despite Mark O’Brien being stripped and ready to go.
And it was fortunate that Cuthbert was able to continue, with John Still forced into making all three substitutions by the 50 minute mark as Long and Ruddock made way for Hall and McQuoid.
The Hatters came out firing in the second half as sub McQuoid whipped a ball in that flew narrowly over the head of Cameron McGeehan, who was quiet in the first 45 minutes, while Doyle, who has never scored for the Hatters, unleashed a 40-yard pile-driver that caused McCormick some trouble.
Doyle’s attempt ramped up the noise at Kenilworth Road, but Marriott’s isolation up top was evident with the lack of clear-cut chances as the game headed into the final 20 minutes.
The league leaders remained a threat on the break despite their goal advantage, Carey and Tanner continuing to be at the heart of the visitors’ attacks in a bid to put the game beyond the reach of the Town.
But just as it looked chances had dried up, the Hatters were level. Penalty-area pinball eventually saw the ball find McGeehan, moved centrally a few minutes earlier having starting on the left, who took a snapshot which McCormick did well to deal with, but McQuoid was on hand to head home into an empty net.
It was McQuoid’s first goal in a Luton shirt, but the work was not done yet however with Tyler required to make another fantastic stop to tip Tanner’s rasper from the right behind for a corner as the game ticked into the final 10 minutes.
The Town weren’t finished there though, and McGeehan was inches away from putting the hosts in the lead, but his shot on the turn following Guttridge’s hard work flew wide from his weaker left foot.
For the neutral, a thrilling encounter was in store at Kenilworth Road, but the nerves of all fans were in jeopardy as both sides sensed a leveller in a more open game.
The Hatters’ chances of a victory diminished soon after though when Hall, who was booked a few minutes earlier for bringing down Tanner, was given his marching orders five minutes from time for kicking the ball away.
You felt there one would be one final chance when the game went into five minutes of added time, but with the Town down to 10 men, it reduced their outlet allowing Plymouth to keep the pressure on.
And the winner came for the visitors when a goalmouth scramble wasn’t dealt with by the home defence allowing substitute Oscar Threlkeld a shot at goal – but Brunt was quickest to the loose ball to scoop over Tyler from virtually the last kick of the game.
The Town have taken just three points from their last three home fixtures, but are back on the road on the road next week when they visit Dagenham and Redbridge next Sunday, with a 2pm kick-off.
Town: Tyler; Long (sub Hall 46), Potts (sub Lawless 28), Cuthbert, Wilkinson, Smith, Doyle, McGeehan, Guttridge, Ruddock (sub McQuoid 49), Marriott.
Subs not used: Justham, O’Brien, Lee, McCourt.
Attendance: 8,703, including 745 from Plymouth.