The Final Victor - S1.E49

As Heero and Zechs come to the end of their final duel, the battleship Libra and Peacemillion descend upon the earth threatening to engulf the world in a never ending winter.... Meanwhile Trowa helps out the wounded Quatre, and Duo delivers the "lords of plague" to peacemillion, in the hopes of averting the tradgedy of the battleships plunge.