You are tasked with the mission of protecting a valley from enemy invaders. If the invaders can make their way completely across the valley they could flank the entire army and wipe us out in one hit. Don't let that happen! Use your mouse to open the build menu and begin constructing walls to funnel the enemy in the direction you want, after that build turrets to defeat them quickly and easily. After you have a few turrets placed, open the upgrade menu and begin upgrading your towers to get more powerful attacks. Don't stop and defeat all of the enemies and save your armies flank!