We learn that Ted had given the Locket to Stella back when they were dating, and that he went to L. After learning that James is getting a divorce, Lily drunk, tells Barney by mistake.Although Robin is relived that Barney doesn't freak out.
However, he stands her up, realizing that (at that time) he didn't want the perfect woman - he wanted Robin.
Season 9 of How I Met Your Mother aired during the 2013-2014 television season. How I Met Your Mother was renewed for a ninth and final season on December 22nd, 2012, with an official announcement made by CBS on January 30th, 2013.
Ted takes Cassie to The Farhampton Lighthouse, to try to attempt to date her, but she just further frustrates him (we haven't seen Cassie since this).
In a flashforward, we see Ted propose to The Mother on The Farhampton Lighthouse.
Barney tries to smooth things over with everybody, but winds up flipping out on his brother and his mother saying the only thing he needs anymore is Robin.