MIT Mystery Hunt 2019

MIT Mystery Hunt 2019 was the 39th iteration of the MIT Mystery Hunt, with kickoff occurring on January 15, 2021. Run by Setec Astronomy, the hunt was themed after holidays with a plot inspired by The Nightmare Before Christmas.

In this iteration of the Mystery Hunt, metapuzzles were consistently placed between two rounds and took some feeder answers from both rounds adjacent to them. Matching feeder answers to metapuzzles was left to the solvers and was a major component of the hunt's structure.

This was the most recent Mystery Hunt to use over-the-phone answer confirmation from HQ instead of an automated answer checker. This was also the most recent Mystery Hunt to not have an explicit upper limit on guess frequency (though the rate-limiting formula in 2020 was not revealed to teams until wrapup.)

The live hunt also ended with both of the leading teams (Left Out and Palindrome) having only First You Visit Burkina Faso and its associated meta as solves that could potentially give them progress. This is the only instance to date where an individual feeder puzzle that was completed by several other teams ultimately determined the winner of the Mystery Hunt. The incident inspired direct follow-ups to First You Visit Burkina Faso to appear in the Mystery Hunt in both 2020 (written by Left Out) and 2022 (written by Palindrome.)

List of Rounds
* The metapuzzles for this round were also fed by puzzles in another round.

† Includes, , and .

Unlock guide
Warning: ''It is not safe to look at the solution pages to completed feeder puzzles for this hunt unless your team has already solved that puzzle's associated meta. Every feeder's solution page spoils which metapuzzle uses that puzzle's answer.''

This hunt exclusively unlocks single puzzles in response to solves, except in cases when new rounds are unlocked. In these cases, two puzzles from that round are unlocked at once.

A full unlock order/guide can be found here, including tools for running the entire hunt (excluding events) in an instance of Microsoft Excel or Google Sheets.

From the organizing team

 * Dan Katz - Part 0: The Watercooler - Part 1: Structure and Story - Part 2: Metapuzzle Development - Part 3: Metapuzzles - Part 4: Puzzles - Part 5: Acknowledgments - Metapuzzles, Backsolving, and Short-Circuiting: A Study of Three Puzzlehunts
 * gredelston - Puzzlehunts: An Overview - Recapping Mystery Hunt 2019, Part 1: Story - Recapping Mystery Hunt 2019, Part 2: Structure - Recapping Mystery Hunt 2019, Part 3: My Puzzles
 * obijywk - Writing about the puzzles I wrote for the 2019 Mystery Hunt
 * tmcay - 2019 MIT Mystery Hunt
 * Reddit AMA

From solvers

 * Alex Irpan - MIT Mystery Hunt 2019
 * betaveros - 2019 MIT Mystery Hunt
 * CheshireSolves - Two Man Mystery Hunt (Postsolve) : 1 - 2 - 3 - 4 - 5 - 6 - 7 - 8 - 9 - 10 - 11 - 12 - 13 - 14 - 15 - 16 - 17 - 18 - 19
 * devjoe - MIT Mystery Hunt 2019, Part 1
 * dr_whom - The Mystery Hunt is the best holiday
 * dr4b - Deanna's 2019 MIT Mystery Hunt Saga
 * Eric Berlin - MYSTERY HUNT 2019
 * fortenforge - Part 1/2 - Part 2/2
 * Joe Bohanon - 2019 Mystery Hunt Wrap-Up
 * lahosken - MIT Mystery Hunt 2019, East Coast Left Out
 * seekingferret - (no subject)
 * Shashakiro - Huge 2018 writeup part 1 (with spoilers) - Huge writeup part 2 (with spoilers): post-hunt solving - Huge writeup part 3 (with spoilers): to 100% completion
 * sniffnoy - 2019 Mystery Hunt Roundup
 * Tanya Khovanova - Mathy Review of the 2019 MIT Mystery Hunt
 * 2019 MIT Mystery Hunt Recap (reddit comment thread)

Leaderboard
The data for this leaderboard comes from the solve log (found in the source code behind the statistics page). Teams are ranked in order of most solves, tiebroken by last solve time. (Only Left Out and Palindrome finished the hunt, and this correctly orders the two teams.)