temporarily supporting a subsurface plug at a support located in the casing, the support located downhole of a stage cementing collar on the casing;

pumping cement slurry down the casing, through the stage cementing collar in a closed stage, through the subsurface plug, past a float valve on the casing, and into an annulus between the casing and the borehole;

displacing the cement slurry in the casing by deploying a wiper plug behind the cement slurry;

engaging the wiper plug in the subsurface plug;

releasing the wiper plug engaged in the subsurface plug as a plug unit from the support; and

further displacing the cement slurry with the plug unit toward the float valve.