ps, who made two changes to their starting line up with Dean Winnard and Kevin Ellison back in the side, played some great football and took the lead with a penalty, which was converted by Michael Rose. Argyle equalised through Oscar Threlkeld on the stroke of half-time, but lost Jordan Slew to a second caution in the opening minutes of the second period.
Morecambe made their advantage pay with a headed goal from their captain Peter Murphy, and held on to record a precious victory that ended an unwanted run of their own.
Both sides showed early intent by having decent chances inside 90 seconds. Shrimps' striker Cole Stockton cut inside and bent an effort at goal that Luke McCormick easily caught, before Jake Jervis skipped down the right flank and crossed low to Slew, whose flick on the turn was not too far over.
Jervis then produced two efforts before the Shrimps forced a string of corners.
From one Aaron Wildig rattled in a tremendous effort, only bettered by McCormick's terrific save, seeing the ball late through a crowd and strongly palming away.
Eventually the Shrimps' pressure told, though, as referee Darren England pointed to the spot having seen an infringement by Gary Miller on Dean Winnard. Midfielder Michael Rose looked assured as he converted the penalty kick.
The Shrimps, without a win at home in Sky Bet League Two since a 2-0 win against Portsmouth on August 16, missed two gilt-edged chances to double their advantage. First, Rhys Turner blasted against the crossbar from no more than four yards with the goal at his mercy, then it took a very good block by Nauris Bulvitis to stop Rose.
Argyle rode the storm and got back in the game. The closest they came was when Carey found space centrally following a slick passing move, and very nearly found the overlapping Threlkeld with a throughball. Roche just got his hands to the ball first, but Threlkeld was not to be thwarted for long.
An Argyle throw into the area was cleared, but only as far as Jervis. After taking one touch to set, Jervis sent over a far post cross that Roche looked favourite to pouch. He misjudged the flight, though, and Threlkeld was in like a flash, powering home the equaliser with a bullet header.
Argyle's hopes of taking advantage of the goal were dashed when Jordan Slew was set off after a 47th min ute dive earned him a second yellow card.
Morecambe took the initiative with Kevin Ellison hitting the post before the Shrimps added a second when a right-wing corner by Rose was met by Morecambe captain Murphy, who jumped above all to power home, and put his side in front.
The excellent Wildig then hit the bar, and it took a very good stop by McCormick to halt the clean-through Cole Stockton from putting Morecambe away and clear.
The visitors staged a late flurry and Roche had to be at his best to save from Jervis's free kick.
Songo'o then had the ball in the back of the net following a free-kick lofted into the box but the whistle, for an earlier foul, had already sounded. Similarly, Bradley then headed another set-piece into the net but was adjudged offside.
Morecambe: Roche, Wakefield, Edwards, Winnard, Jennings; Murphy (capt), Rose; Turner (Massanka 84), Wildig (Mullin 81), Ellison (McGowan 90); Stockton. Subs not used: Molyneux, Nizic (gk), Conlan, Jordan.
Booked: Rose 22, Ellison 25.
Plymouth: McCormick (capt); Miller, Bulvitis (Osborne 76), Bradley, Threlkeld; Donaldson, Songo’o, Smith; Jervis ( Tanner 87); Slew, Carey (Garita 72). Subs not used: Goodwillie, Rooney, Dorel (gk), Fox.
Sent off: Slew 47.
Booked: Donaldson 24, Slew 25.
Referee: Darren England.