Shades of Darkness - Discussion

Could someone summarize the plot of Shades of Darkness? I just finished playing Dance of Darkness, but due to lag, I can't play Shades of Darkness (I can't place heroes; only from the main campaign – Anastasia, Kirill, Anton...). And even if that weren't the case, I can't enter the portal, which makes the campaigns unplayable. I'm curious about what Sandro will do this time.