Roy is excited to play doctor with the new toy set Becky has given him. He makes everyone his patients, giving them health checks in exchange for biscuits. When he checks everyone's heartbeats, he's shocked. His heart is far louder and wilder than anyone else's. He does everything he can think of to calm it down, but nothing works. Will Doctor Roy learn to calm down, or will he accept that everyone's heart beats to a different drum?