Awakening of Evil

It's pointless. I mean, digging tunnels all the way to the center. It will ruin one of the map's highlights – the chase.

So, I'm in the center. Or rather, near the center. The Elf has already captured all my heroes. And I'm still digging up weeds. I took the quest to bring a tear. There are four hints. I'm too lazy to find the fifth. I went through the portal, arrived at a large, ruined city and a lake. I dug up the garden. I went into the hut. They sent me to the city. I killed the undead, brought firewood. They gave me some useless item. What's next?