Here are all of the quests for level 4:
Time for a boost 1/2
Upgrading buildings significantly improves their output. Improve your woodcutter! Objectives:
Upgrade one woodcutter to level 2.
Reward, 39 XP, 50 stone, 40 food.
Time for a boost 2/2
You should build a storehouse to have enough space for your resources. If you run out of storage space, you will have to halt production! Objectives:
Build one, level 1 storehouse.
Reward, 39 XP, 15 coins, 130 wood.
The Kidnapped Girl 1/4
We must send our army out to rescue the poor girl. You need a commander to command the army. Objectives:
Build one, level 1 encampment.
Reward, 42 XP, 135 stone, 210 wood.
The Kidnapped Girl 2/4
You should use siege tools to command a successful attack. Build a siege workshop. Objectives:
Build one, level 1 siege workshop.
Reward, 42 XP, 10 coins, 195 wood.
The Kidnapped Girl 3/4
You must now raise a mighty army. Objectives:
Recruit 3 macemen.
Reward, 44 XP, 100 coins, 95 stone.
The Kidnapped Girl 4/4
It is now time to wage war! Go to the world map and order an attack on the robber baron castle! Objectives:
Defeat one, level 1 or higher robber baron castle.
Reward, 45 XP, 50 coins, 85 wood.