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Dr. Stone Wiki

Medusa Mechanism (MEDUSA (メドゥーサ) MECHANISM (メカニズム) Medoūsa Mekanizumu) is the one hundred and seventy-seventh chapter of the Dr. Stone manga.


The chapter begins with Stanley retrieving the pieces of the airplane crash from the previous chapter. They find black stuff, which Brody informs them is burnt sugar. Stanley's new plan is to fix the plane using Brody's instructions over the phone then continue chasing the junior science brigade. We discover that Ukyo is listening in on their un-encoded calls, not that the information helps them at all. Senku tells them to tell the cease-fire zone team that they need to take apart and analyze the Petrification Weapon before they reach the coordinates.

Homura is shown free diving in the river, finding the device sunk to the bottom. Nikki then discusses tinkering with the device so it can be used for healing any injured or sick people in the future. Internally, Nikki is aware Senku has a use for the device and cannot let the truth slip. Brody agrees, but thinks the timing of the request is suspicious, and insists any fiddling they do with it is monitored. It's revealed that the members of the Kingdom of Science left in North America don't know they're heading for the source, hoping to find the original device.

Minami, Yuzuriha and Yo examine the device together, discussing how best to take it apart. Magma runs in hoping to smash it but gets stopped by Nikki putting him in a chokehold with her thighs. They decide they need to find a skilled watchmaker to take apart the device, but don't know where to find one. Discussing it over dinner, Ryusui comments that they might find one near the airport. Chelsea quickly draws up an incredibly detailed map of the area Ryusui describes.

However, they realize that they have no means to deliver it. Senku decide to recreate the fax machine, in order to get the map to the others. Senku makes a piece of graph paper for Chelsea to color in, making Gen do the laborious task of transmitting the square's color via Morse code. As Yuzuriha then draws the map by coloring in the indicated squares on their side, Tetsuya comments on messaging from abroad. This is the basis of a fax machine.

Yuzuriha, Minami, Magma and one of Brody's men then follow the map to the remains of the airport. They revive the CEO, who directs them to their star employee, Joel Gear. They find and revive Joel, who is immediately embarrassed by his nudity in front of the girls. Minami looks unimpressed and Homura blushes and stares. They explain the situation to him and clothe him, allowing him to take apart the device. Joel is depicted as two sides to himself being shy with women while being rude and cocky to men. After being the device, he notes several things about it. Joel describes new parts being the fact that the circuitry is glass or mineral-like, and the core is a diamond.

He then removes and reinstalls the diamond, testing it on himself and becoming petrified.

Characters in Order of Appearance[]

Chapter Notes[]

  • Senku's team cross the desert as Nikki's team work on taking apart the petrification device.
  • Brody still does not entirely trust the Kingdom of Science but is willing to work with them.
  • Nikki explains that the Medusa Device is intended to be a stand-in for modern medical procedures (which will take years to get back into use due to the unrefined materials of the Stone World).
  • Homura retrieves the petrification device from the river.
  • Senku creates a manual fax machine.
  • The Rodex CEO and Joel are revived by Minami.
  • The petrification device is revealed to be incredibly complex, "as if made with a 3D printer", and the circuitry is glass or mineral-like. The central core is a diamond.
  • The Petrification Weapon is functioning again.
  • Joel petrifies himself.


  • Both Maya and Senku reference 'remote work', a nod to something that most of the world was doing at the time of the chapter's publishing due to coronavirus.
  • The name of the 'classy watchmakers' Ryusui knows of is Rodex, a modified version of Rolex.
  • When searching for Joel, Magma disappears and is replaced by Yo and Homura when he gets revived.
  • There is a spelling error on page 14, where Brody and Yo's thoughts say "his while life" rather than "his whole life"
  • There is a full moon shown, putting the current time around mid-December.[1]
  • The map Chelsea makes is of California, from the Bay Area to Sacramento, with the star representing the capital of California.
  • Magma impulsively hitting the powerful device on the table, leading to a broken axe could be a reference to the Lord of the Rings, when Gimli hits the ring with his axe in an attempt to destroy it.


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