Use the power drill to make ¼-inch holes in the plaster ceiling. Drill holes every four inches into the plaster ceiling, but not into the wooden lath behind the ceiling.
Vacuum the dust that you created when drilling the holes.
Squirt water into the holes with a spray bottle. This will soften the plaster.
Put a tube of latex glue in a caulking gun. Squeeze the caulk into the holes you just drilled. Wipe away any excess glue with a damp sponge.
Brace ¼-inch boards under the repaired area to prop up the ceiling. Cover the top with a polyethylene plastic sheet to protect the ceiling from being scraped by the boards.
Let the latex glue you squirted behind the plaster dry for at least 24 hours.
Remove the plywood boards supporting the ceiling.
Repair the holes you drilled with joint compound and a putty knife.