I actually found a better line! It's close to your solution, but more optimal. Turn 1: 1. Play Arid Mesa, crack it and fetch Badlands 2. Cast Imperial Seal tutoring Underworld Breach to the top of your library Turn 2: 3. Play City of Brass and tap it for {R} to cast Rite of Flame for {R}{R} 4. Cast Underworld Breach 5. Tap Badlands for {B} and exile Elvish Spirit Guide for {G} to cast Demonic Tutor searching for Lion's Eye Diamond 6. Cast Lion's Eye Diamond, and crack it for{B}{B}{B}, and discard hand. 8. Re-Cast Demonic Tutor from graveyard, leaving {B}, and tutor Rain of Filth. 9. Cast Rain of Filth, and sacrifice both lands, making {B}{B}. 7. Re-Cast Lion's Eye Diamond from graveyard, cracking it for {U}{U}{U}. 10. Re-Cast Demonic Tutor from graveyard, tutoring Brain Freeze (you will only have Demonic Tutor left in graveyard) 11. Cast Brain Freeze for Storm=8 and get lucky. 12. GG!

That's awesome! Thanks for sharing!

Here’s my line: 1) ||Arid Mesa for a Badlands. Cast Imperial Seal to get a Lion’s Eye Diamond|| 2) Play ||City of Brass. Cast LED|| 3) ||Cast Rite of Flame. Use one of the red and then your land to cast Demonic Tutor. Hold priority on DT and crack LED for triple black. Should now be floating RBBB|| 4) ||Tutor and cast an Underworld Breach, floating BB|| 5) ||Escape LED, exiling Imp Seal, Arid Mesa, Elvish Spirit Guide. Crack for triple blue. Now floating UUUBB|| 6) ||Escape Demonic Tutor, exiling Rite of Flame, Demonic Consultation, and the random card we drew turn 1. Should now be floating UUB|| 7) ||Tutor and cast Brain Freeze. You still have LED in grave, so you can present a loop to mill yourself out and cast Thassa’s or whatever other win condition you like||