Sugar has been with Abigail since it was a Pikachu. Sugar helps Abigail with her bakery by using its Thunderbolt to cook the berries she used for her treats. Everyone loved to see the team worked together on the yummiest treats they ever tasted. Sugar also loves scratching its head with its tail. It seemed nothing could break apart Abigail and Sugar.
One day, Abigail talked to Sugar about how she wanted to use Aspear berries for a new idea in the annual bake-off coming up. However, the berries needed to be cracked and Sugar's Thunderbolt wasn't strong enough to break them. So, to find a way to break the Aspear berries, Sugar left. Abigail knew that it was for the best, but she was really sad. Her niece, Theresa, who also helps Abigail in the bakery, didn't like the way her aunt was feeling, even though why Sugar left is a secret between Abigail and Sugar.
Theresa met Ash and his friends and ask if his Pikachu could pretend to be Sugar for a while, so she can see her aunt smile again. Pikachu agreed to her request and quickly learned the tail scratch that Sugar always did.
Abigail was thrilled to see Pikachu, thinking he's Sugar. While spending the day together, Pikachu learned some of the battle tactics that Abigail and Sugar used, including stopping to trick an oppenent and using Thunderbolt on an Aspear berry after being attacked by Team Rocket.
Abigail challenged Ash to a battle. Everyone else is shocked at first, but Ash, reluctantly, accepts and battles Pikachu with his Aipom. Partway into the battle, Abigail stops the battle and thanks Ash for battling with her.
That night, Ash decides to tell the truth to Abigail. It turns out, Abigail figured out the truth since Sugar had a different way of using Thunderbolt on the Aspear berries. Abigail then tells them why Sugar left.
Suddenly, Team Rocket captures Pikachu with a giant Aspear berry-shaped robot. Even though our heroes tried to rescue him, they couldn't do it.
Suddenly, a power Thunderbolt attacks the robot. The group sees where it's coming from, a Raichu. Abigail then sees the Raichu scratch its head with its tail; the Raichu was really Sugar. Sugar had evolved and learned Focus Punch during its absent. It was on its way back to Abigail, but it couldn't let Team Rocket get away with Pikachu.
Sugar uses Focus Punch on the robot and it cracks open. Sugar rescues Pikachu right before the machine explodes. Ash and Pikachu are reunited and so are Abigail and Sugar.
The next day, Abigail and Sugar made a cake with the Aspear berries, and let our heroes have a piece. Now Abigail and Sugar are a now even greater team and will now get stronger together from now on.