& Knuckles

"Knuckles the Echidna is the Guardian of the Master Emerald, but ever since Dr. Eggman and Sonic first appeared on Angel Island, trouble has followed."

- Part of the description on YouTube.

& Knuckles or as the title reads as on YouTube Sonic Mania Adventures: Part 3 is the second part/episode of the series, Sonic Mania Adventures.

Synopsis
"Knuckles the Echidna is the Guardian of the Master Emerald, but ever since Dr. Eggman and Sonic first appeared on Angel Island, trouble has followed. Knuckles still doesn’t fully trust Sonic, so he’s been watching over the Emerald constantly to ensure nobody –  robot or hedgehog – gets their hands on it. Now, just as Knuckles finds a safe location,  a mysterious figure appears in the shadows…"

- The synopsis on the video description.

Story
The echidna that appears in the episode's title, Knuckles, places the Master Emerald on the ground. He hears a sound amongst the palm trees and thinks of who it could be. It might be Dr. Robotnik, or the Heavy King, or maybe it could even be Sonic! He clears his thoughts and immediately clings onto the emerald, guarding it the best he can. He tries to cover the emerald up with leaves of the palm trees, but hears the same noise once again. Up in the air, he sees a strange entity flying above him, very closely to the gem. The person amongst the trees reveals itself to be Ray and he lands in front of an confused echidna. He gives a hand shake, but Knuckles points the hand down. Ray then pulls up an image of Mighty, who has been missing. Whilst Knuckles nods no, Ray looks at the big and majestic jewel standing in front of him. He was almost able to touch the emerald, but was angrily thrown away by Knuckles, who is supposed to guard the Master Emerald anyway. He returns to his original state, guarding the emerald, until three badniks show up. Knuckles cracks his knuckles to fight off all three. Once done, he finds the emerald to be missing. he panics and looks under a small rock, just in case. He then looks up to see a strange man driving the Tornado, carrying the emerald. Knuckles assume it's his so-called friend Sonic and furiously chases the plane.

Meanwhile, a robot scans for the white Chaos Emerald, which is located near him. The badnik dashes off to it's destination.

Trivia

 * The title's variant name & Knuckles is a spin to the joke "& Knuckles", which was/is popular amongst the internet.
 * The episode is the third, which can be seen as how it could likely reference Knuckles' first appearance in Sonic games, Sonic 3 & Knuckles.
 * The sound playing when Knuckles let's go of the Master Emerald and puts it down can be heard in earlier games.
 * Some expressions Knuckles make are references to Tyson Hesse's old comic Sonic's Big Fat Adventure.