Swimming lessons are on Saturdays, and every Saturday one little girl has a stomachache. When she gets to the pool it's loud, the floor is wet and slippery, and her swim cap is too tight. Her swimming instructor, Mary, says it's OK to sit by the edge if she doesn't want to get in the water this week. The next Saturday the girl has a stomachache again, but with Mary's gentle encouragement, she eventually manages to make it into the pool to practice her kicks. Little by little, the girl's confidence grows -- until one Saturday comes around when she has no stomachache at all! In a charming and relatable story about trying something new, author-illustrator Hyewon Yum shows that sometimes a little bravery and a lot of patience are all you need to face your fear.