Ever since Ash obtained a Riolu, he had been focusing on training him more over Pikachu. This caused Pikachu to grow sad as he believed that Ash cared more about Riolu more.

Delia, Ash’s mom, was visiting him at Cerise Laboratory where Arh had been staying with his new friends Goh and Chloe. Everything seemed to be going fine until Ash decided to get some training done with Riolu, causing Pikachu to be sad again.

That night, instead of going to Ash’s room, Pikachu made his way to the guest room Delia was staying at.

Delia: just finished putting on her pajamas Ah, much better. Hm? Pikachu, what are you doing here? She asked with a smile as she sat on the bed.

Pikachu didn't say anything, he hopped onto the bed and curled into a ball with a sad expression on his face

Delia: with a sympathetic smile Hm, ok. You can sleep with me tonight. She said, petting him