The victory upped Sam Houston's season mark to 5-4 and gave the Kats two wins in the three-game series for their second series win of the 2012 series.
Michael Oros (2-0) picked up the victory in relief while Allen Scott earned his second save by retiring the Highlanders in the top of the ninth.
Plucheck and catcher Anthony Azar each hit two hits as the Bearkats totaled seven.
Azar led off the second inning with a double to left center and third baseman Kevin Miller followed up with a single up the middle to score Azar as SHSU took an early 1-0 lead.
First baseman Ryan O'Hearn brought in a second Bearkat run in the third inning with a drive to left center. The hit scored center field Colt Atwood who reached first on a fielder's choice then stole second base.
Second baseman Jake Galloway singled in Riverside's first run in the top of the fourth. Designated hitter scored after a one-out walk and a wild pitcher put him on second base.
The Highlanders took the lead for the first time in the top of the fifth inning as center fielder Devyn Bolasky walked and right fielder Phil Holinsworth doubled. Bolasky scored on a ground out and Holinsworth tallied on a single by Gonzalez.
Shortstop Corey Toups walked and Atwood and left fielder Luke Plucheck each had bunt singles to load the bases in the bottom of the fifth. Toups scored on a double play ball to tied the game 3-3.
Plucheck led off the bottom of the eighth with a triple to left center, then scored on a single by Azar.
Caleb Smith threw four- and-two thirds innings. Brandon Bergen also pitched in relief. Trevor Frank (0-2) was the loser for UC R as the Highlanders dropped to 4-7 for the year.
Sam Houston returns to Don Sanders Stadium for a Tuesday game with Houston Baptist. First pitch is 6:30 p.m.