The duo was assigned a mission to capture a Braviary, but N showed up to rescue him. However, a tracking chip in the Pokémon triggered their alarm and Schwarz and Weiss gave chase to N. N narrowly made it to a nearby Pokémon Center before the duo retrieved the injured Pokémon. When the Pokémon Center's power went out, Schwarz and Weiss broke in to get Braviary, but he already left with the help of N, Ash, and his friends.
Schwarz and Weiss then hid in some bushes, waiting for the right moment to strike. As soon as N came by with Braviary, the duo sent out their Seviper and Zangoose. They attacked N, leaving him injured. Ash, Iris and Cilan came to his aid and battled the duo. Schwarz and Weiss were tough but were beaten by Excadrill, Pikachu, and Braviary.
Weiss later reappeared in Team Plasma and the Awakening Ceremony!, as part of the large group of Team Plasma Grunts that assaulted the White Ruins in order to acquire the Light Stone. He managed to catch Iris, Cilan, and Cedric Juniper together with two other Grunts and imprisoned them in steel rings to keep them under their control. He then witnessed how Team Plasma's leader Ghetsis summoned Reshiram. He was presumably arrested after Reshiram was freed from Team Plasma's control and Team Plasma was defeated.
Zangoose is Weiss's only known Pokémon. Weiss sent it out after he and Schwarz caught N getting away with an injured Braviary. It was then used to battle Ash and his friends and was eventually defeated in a battle by Ash's Pikachu with help from the Braviary.