S03E18: The Dweller in the Depths
The Quintessons trick the Decepticons into releasing the dangerous Trans-Organics. One of them, the Dweller, begins taking control over Autobots and Decepticons alike.
Previous Episode 
Season 1
Transport to Oblivion
S1E1 / 06 Oct 1984
Roll for It
S1E2 / 13 Oct 1984
Divide and Conquer
S1E3 / 20 Oct 1984
S.O.S. Dinobots
S1E4 / 27 Oct 1984
The Ultimate Doom: Brainwash (1)
S1E5 / 03 Nov 1984
The Ultimate Doom: Search (2)
S1E6 / 10 Nov 1984
The Ultimate Doom: Revival (3)
S1E7 / 17 Nov 1984
War of the Dinobots
S1E8 / 24 Nov 1984
Countdown to Extinction
S1E9 / 01 Dec 1984
Fire in the Sky
S1E10 / 08 Dec 1984
Heavy Metal War
S1E11 / 15 Dec 1984
Fire on the Mountain
S1E12 / 22 Dec 1984
A Plague of Insecticons
S1E13 / 29 Dec 1984
Season 2
Autobot Spike
S2E1 / 23 Sep 1985
The Immobilizer
S2E2 / 24 Sep 1985
Dinobot Island (1)
S2E3 / 24 Sep 1985
Dinobot Island (2)
S2E4 / 26 Sep 1985
Traitor
S2E5 / 27 Sep 1985
Enter the Nightbird
S2E6 / 29 Sep 1985
Changing Gears
S2E7 / 30 Sep 1985
A Prime Problem
S2E8 / 01 Oct 1985
Atlantis, Arise!
S2E9 / 02 Oct 1985
Attack of the Autobots
S2E10 / 03 Oct 1985
Microbots
S2E11 / 06 Oct 1985
The Master Builders
S2E12 / 07 Oct 1985
The Insecticon Syndrome
S2E13 / 08 Oct 1985
Day of the Machines
S2E14 / 09 Oct 1985
Megatron's Master Plan (1)
S2E15 / 13 Oct 1985
Megatron's Master Plan (2)
S2E16 / 14 Oct 1985
Auto Berserk
S2E17 / 15 Oct 1985
City of Steel
S2E18 / 16 Oct 1985
Desertion of the Dinobots (1)
S2E19 / 20 Oct 1985
Desertion of the Dinobots (2)
S2E20 / 21 Oct 1985
Blaster Blues
S2E21 / 22 Oct 1985
A Decepticon Raider in King Arthur's Court
S2E22 / 23 Oct 1985
The God Gambit
S2E23 / 27 Oct 1985
The Core
S2E24 / 28 Oct 1985
Make Tracks
S2E25 / 29 Oct 1985
The Autobot Run
S2E26 / 30 Oct 1985
The Golden Lagoon
S2E27 / 03 Nov 1985
Quest for Survival
S2E28 / 04 Nov 1985
The Secret of Omega Supreme
S2E29 / 05 Nov 1985
Child's Play
S2E30 / 06 Nov 1985
The Gambler
S2E31 / 10 Nov 1985
The Search for Alpha Trion
S2E32 / 11 Nov 1985
Auto-Bop
S2E33 / 12 Nov 1985
Prime Target
S2E34 / 13 Nov 1985
The Girl Who Loved Powerglide
S2E35 / 17 Nov 1985
Triple TakeOver
S2E36 / 18 Nov 1985
Sea Change
S2E37 / 19 Nov 1985
Hoist Goes Hollywood
S2E38 / 20 Nov 1985
The Key to Vector Sigma (1)
S2E39 / 24 Nov 1985
The Key to Vector Sigma (2)
S2E40 / 25 Nov 1985
Aerial Assault
S2E41 / 09 Dec 1985
Masquerade
S2E42 / 15 Dec 1985
Trans-Europe Express
S2E43 / 22 Dec 1985
War Dawn
S2E44 / 24 Dec 1985
Cosmic Rust
S2E45 / 25 Dec 1985
Kremzeek!
S2E46 / 26 Dec 1985
Starscream's Brigade
S2E47 / 06 Jan 1986
The Revenge of Bruticus
S2E48 / 07 Jan 1986
B.O.T.
S2E49 / 08 Jan 1986
Season 3
The Five Faces of Darkness (1)
S3E1 / 14 Sep 1986
The Five Faces of Darkness (2)
S3E2 / 15 Sep 1986
The Five Faces of Darkness (3)
S3E3 / 16 Sep 1986
The Five Faces of Darkness (4)
S3E4 / 17 Sep 1986
The Five Faces of Darkness (5)
S3E5 / 18 Sep 1986
The Killing Jar
S3E6 / 28 Sep 1986
Chaos
S3E7 / 29 Sep 1986
Dark Awakening
S3E8 / 30 Sep 1986
Starscream's Ghost
S3E9 / 01 Oct 1986
Thief in the Night
S3E10 / 05 Oct 1986
Forever Is a Long Time Coming
S3E11 / 07 Oct 1986
Surprise Party
S3E12 / 08 Oct 1986
Madman's Paradise
S3E13 / 12 Oct 1986
Carnage in C-Minor
S3E14 / 13 Oct 1986
Fight or Flee
S3E15 / 14 Oct 1986
Webworld
S3E16 / 19 Oct 1986
Ghost in the Machine
S3E17 / 21 Oct 1986
The Dweller in the Depths
S3E18 / 29 Oct 1986
Nightmare Planet
S3E19 / 30 Oct 1986
The Ultimate Weapon
S3E20 / 09 Nov 1986
The Quintesson Journal
S3E21 / 10 Nov 1986
The Big Broadcast of 2006
S3E22 / 11 Nov 1986
Only Human
S3E23 / 12 Nov 1986
Grimlock's New Brain
S3E24 / 13 Nov 1986
Money Is Everything
S3E25 / 16 Nov 1986
Call of the Primitives
S3E26 / 17 Nov 1986
The Burden Hardest to Bear
S3E27 / 18 Nov 1986
The Face of Nijika
S3E28 / 19 Nov 1986
The Return of Optimus Prime (1)
S3E29 / 24 Feb 1987
The Return of Optimus Prime (2)
S3E30 / 25 Feb 1987
Season 4
The Rebirth (1)
S4E1 / 09 Nov 1987
The Rebirth (2)
S4E2 / 10 Nov 1987
The Rebirth (3)
S4E3 / 11 Nov 1987
Peter Cullen
Optimus Prime (voice)
Frank Welker
Galvatron / Chromedome (voice)
Richard Gautier
Hot Rod (voice)
Jack Angel
Ultra Magnus / Cyclonus (voice)
Susan Blu
Arcee (voice)
Corey Burton
Spike Witwicky (voice)
David Mendenhall
Daniel Witwicky (voice)
