The lesson discusses the importance of defining risk when trading technical structures and how overthrow can be used to help with stock placement. The video covers the two criteria for a level to be a trade, and the benefits of using overthrow as a built-in invalidation level. The lesson also explains how markets are not clean and why technical analysis principles can fail, leading to the importance of understanding how to position for a move properly. The video includes examples of trades using overthrow for stock placement and furthermost deviation, as well as the importance of knowing your market and some discretionary factors involved in trading. Overall, the lesson emphasizes the need for a rigorous, logical, and systematic approach to trading technical structures.