Cardfight!! Vanguard - 1x03 - Season 1, Episode 3- Followmy.tv

Aichi's little sister, Emi, is worried by Aichi's different behavior as of late. After school, Emi sees Aichi with Morikawa and Izaki, who want him to go with them to the Card Capital. However, Emi misinterprets the situation as Aichi hanging with the wrong crowd. Concerned for her brother, she secretly follows the trio to the Card Capital. There, Emi is astounded by all the people in the shop, icluding Aichi, Morikawa, and Izaki, playing Vanguard. It is then that the card shop's manager, Shin Nitta, appears and introduces Emi to the world of trading card games. Emi and Shin then observe a cardfight between Aichi and Morikawa. The battle ends with Aichi winning without taking any damage. Watching Aichi play, Emi sees how much her big brother has changed because of Vanguard. And so, she has become supportive of Aichi playing the game.