Ep. 18: Ash and friends encounter Burgh in Pinwheel Forest while pursuing a wild Sewaddle.

18

Ash, Iris, and Cilan enter Pinwheel Forest, where Pikachu is attacked by a wild Sewaddle. Ash attempts to capture it, but the Pokémon escapes using String Shot. The group finds a large tree containing a giant cocoon, which turns out to be Burgh, Castelia City's Gym Leader, sketching wildlife. Sewaddle attacks Ash again but nuzzles Burgh, indicating it dislikes Ash. After Ash saves Sewaddle from Woobat, the Pokémon begins to warm up to him. The next day, a Patrat abducts Sewaddle to reveal another Patrat is ill. Sewaddle attaches to a Deerling and falls toward a waterfall. Ash dives to save it and is rescued by Burgh's Leavanny. Grateful, Sewaddle allows Ash to capture it, requiring Ash to transfer a Pokémon to Professor Juniper. The group then departs, with Burgh telling Ash he awaits in Castelia City.