The monsters are out to destroy your castle! Stop them by building towers. For each tower you need wood, that you get from your wood supply. Keep these stocks up (visible bottom right) and replenish them as soon as you can. This also applies to the other raw materials that you see there. You can collect materials in the field on the top left. Do so by making rows or columns of five similar materials. Move the rows or columns in such a way, that you create series, that will then disappear into your material supply. You can play this game in the 'story mode' and in the 'endless mode'.
Use the mouse to play this defense game.