Last fall, Canadian agency Cossette recast the image of children with serious illness in an unexpected, empowering light when it debuted the SickKids VS campaign, for the SickKids Foundation. Like Channel 4's "Meet the Superhumans" before it, it depicted the kids and their caregivers ready to tackle their ailments with the strength and ferocity of fierce warriors. Now, a new ad from the campaign offers a different, more heart-wrenching portrait of strength, that of the heroes on the other side of the story -- the moms.

The ad breaks ahead of Mother's Day and highlights the moms' tremendous courage as well as the agony they endure in order to be a pillar of strength for their children. While they greet their children with smiles and warmth each day, their moments away from them are fraught with loneliness and intense fear.

The agency cast five real mothers and SickKids patients, and the ad is based on their real-life experiences. Watch, and cry.