After loosing the battle against the Chatot when Spheal fell asleep from the sing, Mercury decided they couldn't grow much in the Minoru region, so they had to travel to another one. And Sinnoh was her first choice. "Spheal, we're going to travel for a bit. Sinnoh is our next destination, there are powerful pokemon there and they'll help us grow in strength as we battle them. What do you think?" She asked her partner and got an excited reply "Spheal Spheal!" It was clear that Spheal wanted to go with Mercury, so they did. After packing their stuff they traveled by plane to the Sinnoh region