In an alternate dimension, the Night King mounted on Viserion and his army of Wights, Undead Giants, and White Walkers are attacking Winterfell, except all defending forces (including Daenerys and her two dragons and Jon Snow) have vanished and are replaced by the one and only Smaug.
Essentially all of Winterfell is deserted except for Bran who is sitting in the Godswood and Smaug to protect him.
All set up defenses (the unlit trench, any pre installed barricades and obstacles if any) are still there.
All Night King abilities (ice spear, blizzard) are allowed.
Can Smaug wipe out the whole army and kill the Night King and protect Bran?