Clive Davis, the chief theater critic at the Times, calls Backstroke “ferociously unsentimental.” Written and directed by Anna Mackmin, the new play is about Beth, a woman with Alzheimer’s. She’s had a stroke, and when her daughter, Bo, visits her in the hospital their shared history unfolds, as well as the dependence between a too critical mother and a too stoical daughter. The story moves between Beth’s hospital room and her kitchen, and between Bo’s past and present struggles with work and motherhood. The divine Celia Imrie is Beth and Tamsin Greig is Bo. —Jeanne Malle