DP090 is the 90th ep[isode of DP it first aired in Japan on Dec 24th 2007.
In this episode Dawn's Piplup evolves when it is in battle with a Taillow who belongs To Diego however what happens when Prinplup needs to get it's check-up at the Pokemon Center
James catches a Scyther
Dawn's Piplup Evolves Into Prinplup
Dawn's Ambipom learns Fling