The Mystery of Planet Master

Continuing on where the previous episode left off, the Autobot and Decepticon headmasters engage each other in battle. As this goes on it is watched by the Autobots on Athenia who are glad that these new warriors are on their side.
 

Outside the Vector Sigma entrance Galvatron tries to break through but a group of Autobots led by Optimus Prime fend him off. Optimus tells Hot Rod to take over whilst he goes to try and fix the super computer.
 

The Decepticons begin to advance though thanks to the help of all the combiner teams merging into their larger robot forms, but then the massive battleship we saw at the end of the previous episode moves in and starts blasting lasers at all the Decepticons, beating them all down. Galvatron tries to destroy the ship but he ends up been blasted. With his forces beaten, Galvatron tells everyone to pull out and leave Cybertron.
 

Hot Rod invites the new warriors to Athenia where another new character is introduced: Fortress Maximus. Fortress Maximus is the leader of the Autobot headmasters and Kup recognises him. We then see Fortress' back story; four million years a go he led a group of smaller Autobots away from Cybertron on a ship and fled to a planet Master to live in peace.
 

Spending thousands of years building cities, the smaller Autobots develop a unique transforming process where they transform into a head and attach to the body of a normal Transformer sized body, giving them greater amounts of power.
 

Fortress goes on to explain that a group of evil Transformers rose up against them, led by a Decepticon called Zarak. Fortress and the Autobot headmasters fought against them and exiled them from Master, but they went on a rampage across the universe, attacking other planets. Fortress and his troops followed them, and now their enemies have joined up with Galvatron so they're here to help the Autobots.
 

Back on Cybertron Optimus Prime is fighting through Vector Sigma's Centurion robots (which were last seen all the way back in season 2's The Key to Vector Sigma) and after fighting a group of them, the spirit of Alpha Trion shows up. For those of you not in the know, Alpha Trion was the creator of Optimus Prime and he's here to help out Optimus.
 

In the Athenia Autobot base, Fortress learns about how Optimus has gone to Vector Sigma without the Matrix of Leadership. Hot Rod says that the Matrix is recharging somewhere on Earth but only Optimus knows where it is. Hot Rod tries to contact Optimus but is unsuccessful. Hot Rod decides that he has no other option than to go and search for the Matrix on Earth, so he heads off and takes Blaster with him.
 

Using the space bridge, Hot Rod and Blaster arrive at Autobot city where Ultra Magnus greets them and tells Jazz to bring up the possible Matrix locations on a computer screen. Before Jazz does those Blaster says that there is an intruder in the room and the Decepticon spy Ratbat flies off. Sending Steeljaw after him, Blaster finds follows after him and finds...
 

...his old Decepticon counterpart Soundwave, who starts taking pot shots at his cassette robots. Blaster runs in to back them up but Soundwave uses a smoke bomb and promptly vanishes, but not before warning Blaster that sometime he'll get him.
 

Back in the main room Jazz has the main Matrix location points bought up and Hot Rod decides that they need to start searching through them all in an attempt to find the Matrix, so he and Blaster head out. Ultra Magnus says he'll try and confuse the Decepticons and has the Aerialbots sent out to a Decepticon energon reserve in a desert.

And sure enough, the Aerialbots deliberately let themselves be picked up by enemy sensors, so Sixshot sends out the Stunticons. The two teams fight each other whilst...

...Hot Rod and Blaster search the North Pole for the Matrix. Soundwave reports to Galvatron about the Aerialbot diversionary tactic, so Galvatron tells him to take himself and the Stunticons there as well and destroy Hot Rod. Back in the North Pole Hot Rod says that the Matrix cannot be here as he isn't picking up any readings for it so he and Blaster start to head back, only to find the Predacons in wait.

Blaster deploys all four of his cassette robots and a fight begins. The Predacons prove to not be powerful enough so they try to transform into Predaking, only for Hot Rod to drive straight into them and prevent them from merging. The Stunticons appear on the scene but thanks to the Aerialbots, they are stopped before they can attack Hot Rod, who drives off.

Hot Rod ends up in a clearing where Soundwave sends his cassettes to distract him whilst he takes aim, only for Blaster to show up and take the hit instead. Blaster tells Hot Rod to leave whilst he and Soundwave settle things once and for all.

A quite violent fight breaks out between the two, where they both smash each other's chests, and Blaster punches Soundwave so hard that he loses his right arm. Soundwave then tackles Blaster and smashes him into a ice cliff. All this is being watched on a view screen by Galvatron, whilst Hot Rod notices that Blaster is being beaten up pretty badly, so he heads back the way he went.

Meanwhile the fight between Blaster and Soundwave continues, and Blaster does an elbow drop on Soundwave's chest, but Soundwave punches him back to the ground. Soundwave gets up, but he's taken such a pummelling that he simply explodes into pieces. Galvatron is pissed. However, Blaster doesn't survive either and holds on long enough to tell Hot Rod to forget about him and to find the Matrix and save Optimus Prime before dying. Hot Rod says that Blaster's death will not be in vain and then tells Steeljaw to take care of things here whilst he goes off to try and find the Matrix somewhere else.

As this is going on Laserbeak picks up Soundwave's head whilst Ratbat and Buzzsaw pick up Rumble and Frenzy and then fly off into the distance. Meanwhile the new of Blaster's death reaches the Autobots on Cybertron, so the Autobot headmasters decide to head to Earth and help in the search for the Matrix. Back on Earth, Hot Rod transforms and continues his search whilst the narrator says that Hot Rod has to hurry as Optimus is in great danger.

And just for clarity's sake, this is what Galvatron's reaction to Soundwave's death sounds like in the English dub. Incredible, huh.

This is the last time we ever see the Dinobots in animated form.

Those Centurion robots Optimus fights must have gotten a lot weaker over the years, because Optimus ploughs through them all easily whilst they were presented as being near-invincible in The Key to Vector Sigma.