Barney meets the mother of "how i met your mother"

As far as we know, Lily has met the "mother". The recently aired episode of how i met  your mother shows how Barney met the "mother" long before Lily, to be exact , before the last chapter of the playbook "The Robin " was written.

The "challenge accepted" nature of Barney leads him to the "mother" in the series. As it turns out, the "mother " actually helped Barney to go for Robin when he was "accepting a challenge" from Lily and Robin. He tries to pick up a complete stranger from a drug store who gives some life lessons to Barney and finally Barney writes "The Robin" in his playbook which eventually leads to their marriage. This complete stranger is the "mother", the girl with the yellow umbrella.

As usual, future Ted narrates ," And that's how Barney met your mother.".......................

Also, the "Breaking Bad"star, Bryan Cranston (Heisenberg) shows up in the episode as Ted's former boss Hammond Druthers.