Sophia reveals that her brother is a personal enemy of the Roman Dictator Sulla, having tried to convince the slaves to rebel before; Jonathan then alerts them of a dinosaur in the middle of Rome. Meanwhile, Foolscap returns to the Space Pirates' main ship, arguing with fellow Pirates Gabbro and Shear over who's the best amid the shadowy reveal of their boss, stroking his pet sauropod like a classic villain. Gifted with a new round of Dinosaur Cards, Shear promises to retrieve the Yellow Cosmos Stone where the others failed…a promise which must be kept. Or else.
In Rome, the Alpha Trio prisoners are tossed a slab of raw meat like the lions in the next cage, but Terry is being kept in a giant cell and starved to make him angrier for a better show in the Colosseum. Dictator Sulla arrives to witness the beast his soldiers will defeat to show Rome's power to any swayed by Spartacus' previous attempt at rebellion. On the Backlander, Helga finds Dr. Z "goofing around" with "toys" (working on the Spectral Armor countermeasure) and puts him to work dusting instead. Arriving in Rome, the D-Team overhear a description of a large theropod set to fight the Roman Army. They try convincing a guard to let them in, but hearing Sophia is Spartacus' sister sets them against the group, their pet-sized dinos running interference as they escape. As Terry's fight prepares to start, Sulla taunts the prisoner Spartacus about the lions he'll fight later.
In the Colosseum, the D-Team has snuck in and watch Sulla amass cheers from the crowd, while Spartacus slings a fork into Terry's tail as he's being led out, making him thrash and break down most of their cages' bars; not seeing that part, soldiers bring the Alpha Trio and their Alpha Scanners to keep the mad Tyrannosaurus in check if needed. As Terry is led out into the Colosseum floor to face a hundred Roman soldiers, Sophia slips away and runs into an escaping Spartacus, delivering the Yellow Cosmos Stone, but guards give chase. As Sulla starts the fight against Terry, Max sends Chomp into the arena to battle him into a card. The others try to save the Alpha Trio, Zoe's overuse of "old lady" triggering Ursula to kick down the guards (and Zander and Ed); Terry fights back too well, however, forcing Ursula to recall him directly. The guards also surround Spartacus and Sophia.
Spartacus downs numerous guards but stops fighting when Sulla arrives and holds a sword to Sophia; Sulla ignores her when Spartacus surrenders, giving Max the chance to drag her away. The D-Team flees through Rome, pursued by soldiers and secretly watched from above by Shear, as they take a turn down a dead-end alley…
Max/Chomp vs. Terry
A weakened Terry is surrounded by a hundred Roman soldiers, the Alpha Gang being prisoners, so Max summons Chomp into the Colosseum, ramming Terry and breaking his chains. Chomp bites Terry's leg, but is kicked away. He charges again and rams Terry, lifting and tossing him. Wanting to end the battle before both dinosaurs are captured, Max activates Lightning Strike, hitting but not defeating Terry. Having been rescued by now, Ursula is reminded of the situation and both Terry and Chomp are recalled.
- Though the English title uses the word "Coliseum", this is actually the general term for such a building, as the spelling "Colosseum" is the actual name of the famous Flavian Amphitheatre specifically featured, which itself was only constructed from 70-80 AD, 143 years after this episode's setting.
- Max first speculates the mystery dinosaur signal in Rome to be Foolscap's Shunosaurus…whose card they've already acquired. Likely a script/dubbing mistake.
- While Spartacus' slave rebellion indeed took place in 73 BC, the real Dictator Sulla had died five years earlier in 78 BC, and had ceased being the Roman dictator in 81 BC (after which the title would go unused for 32 years), making it an odd choice for him to be chosen to be featured this way in this story arc.
- According to some accounts, the real-life Spartacus' slave breakout from a gladiator training camp involved using kitchen utensils, possibly referenced by this Spartacus throwing the fork at Terry's tail.
- This episode features one of the few full-length dinosaur summoning transformation sequences of Mesozoic Meltdown, for Chomp.
- A rather long animation of Chomp and Terry battling is, minus a new camera angle or two, recycled almost exactly from Temple Tempest, featuring Chomp biting Terry's leg and being kicked away before getting back up, ramming Terry, and tossing him away. He then uses Lightning Strike, but it's different from there.
- This is the only episode of Mesozoic Meltdown not to feature a Space Pirate-controlled dinosaur (save recap footage and chibi Brontikens), as even the premiere before they met the D-Team showed Torvosaurus, while Yangchuanosaurus only shows up to break the cliffhanger at the beginning of next episode.