Cow Boy: A Boy and His Horse — Chris Eliopoulos

Desperate questions make reluctant alliances! Garruk the Wildspeaker agrees to work with the woman who once cursed himâ€"Liliana Vess!
Together, they must find Isona Maive before she finds an even more dangerous ally than Marit Lage or Tezzeret!
With the man she loves, Jace Beleren, unsure if he's hearing a voice from beyond the grave, Vraska calls on Kaya. Kaya may be the only Planeswalker who can slay a ghost, but she also pulled Vraska out of Jace's arms in what might have been their final moments together.
And Kaya's not any happier to see Vraska, who foreswore their friendship as thanks for Kaya saving her life. But if Niko's right, someone is manipulating all their fates, there's no time left for grudges.