Jed MacKay 
Magic #19 [PDF ebook] 

Chandra, Garruk, and Niko have finally made it to Ravnica, but Tezzeret was more than ready for them… If they want to succeed in freeing Ral, Kaya, and Vraska from their sadistic prisonsthey’ll have to face a challenge that no one could have predicted, and a final showdown with the Master of Metal himself! Magic fans won’t want to miss the beginning of this epic two-part finale, and the start of a new mystery that will put the fate of the entire multiverse at stake!