Try for the Family Stone!

Still on the way to Sunyshore City so Ash can battle for his final Sinnoh Gym Badge, Ash and friends meet a female trainer and her Misdreavus who are battling a Murkrow for a Dusk Stone, which has the power to evolve Misdreavus into Mismagius. It also has the power to evolve Murkrow into Honchkrow, so she is frantic to get the stone.