As has become commonplace at this point, The episode where the party has a climactic boss battle that is cut short by technical difficulties. At this point I shouldn't be surprised. At least we got a few minutes of action out of it.
The party jumps into a surprise encounter with the Sundering Titan, little Mirrodin's erstwhile guardian who roams the razorfield plains at its heart. The towering metal giant sustained many heavy blows from the party before initiating a booming verbal countdown.
...NIIIIIINNNNNE...
And the party redoubled their efforts to smote the beast before it completed its dread ignition sequence. Thankfully, with a few well timed shots to its exposed power core, the group brought down the metal giant and were able to claim the final piece of the missing memories scattered about this land.
The memory depicted a calm scene, showing the same flying ship they'd seen earlier trawling above the clouds. It housed a diverse crew, including many humans but also a goblin, minotaur and a catfolk. A debonair looking corsair turned to look at the POV of the memory and asked
"You all right, Karn?" in an easygoing, companionable way.
With the name of the memories' owner now in their possession, the group returned to the darksteel tower where golos and Sad Robot, or Karn, still waited.
Restoring the memories to Karn, definition began to return to his features and his body became more silvery. He stood tall before the group, whole once again. And then he killed Golos.
He then explained to the shocked and horrified party that Golos was not their friend, nor his--but a sinister automaton created by a mad wizard named Memnarch from the past, who sought to return to life by taking control of karn's abilities.
With Karn at their side, the group watched as he shrank the invasive quicksilver landscape of Mycosynth down to just the imported landmass here--which Azor had stolen from Mirrodin. Now the particles of this other plane would not try to expand and infect the rest of this world. He also shrank the darksteel tower down into a portable token, which Vali recognized as his lost Instant Fortress.
Karn was a powerful ally. And they would need those, if they were to find and defeat Azor, master of this plane and expat of theirs.