Migi to Dali (E01)

The twin boys Migi and Dali live in an orphanage until one day they are adopted by a wealthy and gentle elderly couple, the Sonoyamas. However, they are not taken in as the two boys 'Migi' and 'Dali,' but rather as a single boy named 'Hitori Sonoyama.' While hiding their true identities and pretending to be Hitori Sonoyama, they hatch a plan to win over the Sonoyamas. Their scheme is highly successful; within just a day, they won the favor of the elderly couple. Inside the tent in their room, the two share a sly smile. (Crunchyroll)