'How I Met Your Mother' Season 9 Spoilers: Lily and the 'Mother' Fighting in Episode 1 Trailer / September 23 Premiere [VIDEO]

The mother of all Mondays is coming up in a couple weeks. As for the other CBS sitcoms, no one cares. However, the How I Met Your Mother Season 9 premiere is set for September 23, and that's cause for celebration.

In the newest ad for the September 23 lineup, CBS gives us a short sneak peak into the hour-long premiere episode "The Locket/Coming Back". It looks like Lily might be the first of the gang to meet the mother, played by the lovely Cristin Milioti.

In a barrage of Season 9 cast rumors and confirmations, we have yet to hear anything about the mother. Last time we saw her was in last season's finale. Now it looks like her and Lily are fighting on what appears to be a train ['cause last time we saw the mother was at Farhampton station]. Did the mother flirt with Marshall? Did she try to steal Lily's overhead compartment. We know Lily is a spunky gal but why would she fight the future Mrs. Mosby.

Guess we'll have to wait for the How I Met Your Mother Season 9 premiere to find out.

As for the rest of the Season 9 cast we know Anna Camp [True Blood], Roger Bart [Revenge], Wayne Brady, John Lithgow, Sherri Shepherd have all signed on for guest spots for the final season of the popular CBS sitcom.

Let me reiterate! The How I Met Your Mother Season 9 premiere is set for September 23 on CBS.

Check out the latest trailer for the premiere episode. Offer up your explanations for why Lily and the mother are fighting on the train!