Pokémon Lepidolite

Two young Trainers arrive in Kanto to forge their own paths, separate from their famous fathers.

Toru Oak is the Alola League Champion. He has never lost a battle. He says he's looking for stronger opponents, but that's not the only reason he takes off to Kanto. He's running from his broken home.

Nakhil Arichi once wanted to be an astronaut, but since his father disappeared, all he cares about is making a name for himself as the greatest Trainer in the world. He has failed to triumph over two Pokémon Leagues already and lost spectacularly to his half-brother Barry at the Battle Tower in Sinnoh. This time, Nakhil is determined to succeed, and he will gladly crush Toru to do so... but that isn't what he really needs. He needs to grieve...

...And there are things much bigger and darker than lost and grieving kids in the shadows of the Pokémon world, like whoever killed Palmer, Nakhil's father.

This is the sequel to Pokémon: The Hour Before Dawn. It can be read on its own, but I'd recommend reading the prequel first.