In Osomatsu-san: Hipipo-zoku to Kagayaku Kajitsu, the sextuplets embark on a grand adventure in search of a legendary fruit that is said to grant the greatest wish of whomever consumes it.
(Source: Crunchyroll, edited)
Note: To commemorate the 6th anniversary of Osomatsu-san anime, two new animation projects that will have a theatrical release were announced at the "Fes Matsu-san '21" event, with one in 2022, and the other the following year.
