Mimi and Lulu are best friends despite liking different colors and they love playing together, whether it's pretending to be on a phone or being princesses.

Eight-year-old Grace is excited to learn that her best friend, Mimi, is going to become an older sister, but when both try to be "mother's helpers" for a family renting a house on their street, little Lily likes Grace best, causing Mimi to doubt herself and Grace to form a plan to fix things.

Lots of exciting things are happening to Grace and her friends. Most exciting of all, Mimi's older cousin Gwen is coming to stay with Mimi, and Miss Lois's class is going green! For their "green" project, Grace and Mimi aim to inspire their friends and classmates to conserve plastic bottles. But a far more important issue is that Gwen has taken a strong liking to Mimi's favorite stuffed toy, Willoughby. Just Grace uses her empathy superpower to figure...