Episode 4620 - Hooper's Lockdown HBO Premiere: Saturday May 21, 2016 PBS Premiere: Monday February 27, 2017 When Grover's new security gate system accidentally locks Chris out of Hooper's store, Elmo and Abby help solve math problems to open the gates in time to stop Cookie Monster from eating Alan's birthday cake. Also featuring Nick Jonas ("Check That Shape"), Cookie Monster's Crumby Pictures ("The Hunger Games: Catching Fur") and Elmo the Musical ("Karate Master"). Brought to you by the letter S and the number 8. This episode features an all-new street story. If you saw "Hooper's Lockdown", let others know. Please like this post and share your thoughts below.