Ep 19. The Fortress

Ted realizes that he has been living in his apartment for too long and that it is time to move out. Barney insists that Ted come up with a new apartment that is even better than his current one. Meanwhile, Marshall and Lily are having trouble sleeping because their new landlords are always loud. They decide to build a "fortress" in their bedroom to block out the noise. However, they soon realize that the fortress is causing more problems than it's solving. Robin is having trouble adjusting to wearing an engagement ring and is desperate to remove it without insulting Barney.