This fifth installment of the monsterverse begins where Godzilla vs Kong left off. 
Kong is patrolling the hollow earth looking in vain for his own kind. Godzilla patrols the earths surface, battling Scylla before dispatching it with the kiss of death used in the first film.
Jia the Iwi girl gets her own role as protagonist, as she starts having unexplainable visions, one of which causes her to panic and dismantle the room.
Dr. Andrews also returns in a main protagonist role asking Bernie what could possibly be the driving force behind Jia's visions.
Kong has been suffering from an abscessed tooth and it's the pain that drives him to the surface. He is knocked out and has an extraction performed in a particularly zany scene by Dr Andrew's on again off again bf animal veterinarian portrayed by Dan Stevens.
Kong and the main cast, Jia, dr. Andréws, Bernie, Trapper and a Heav pilot goes down to the hollow earth where they discover an uncharted sector. Kong discovers a tiny young monkey that bites him. At first, Kong is particularly harsh toward the younger one using him as a club to knock the hell out of the enemy Kongs but over time the relationship between the two Kongs begins to thaw.
Godzilla, meanwhile has attacked a nuclear power plant (a nod to Godzilla 1985) and is seen orally ingesting pure radiation. He then takes off toward Antarctica and home to Tiamat, dispatching his serpentine for with ease before settling in to her lair to absorb her radiation.
The human protagonists are captured by Iwi tribespeople who have been living in the deep recesses of hallow Earth all along. 
Jia is able to communicate with them and Dr Andrews ascertains that Jia is part of an Iwi prophecy that foretells she must summon Mothra to stop the false king Skar King, a particularly cruel and brutal slave master, who controls Shimo, the most ancient of all titans through a crystal that causes her pain.
Kong confronts Skar King who then unleashes Shimo and has his hand frost bitten. Suko and Kong make their way back to the Iwi tribe and Kong signs to Jia "I lost home" in a very emotional scene.
Trapper manages to save Kongs arm with the power glove and so Kong makes his way to the surface to enlist Godzilla in his fight. Godzilla isn't having it and rushes in to pummel the hell out of Kong. He is just about to blast Kong to kingdom come when Mothra stops him.
Godzilla and Kong travel to hollow earth to confront Skar King and Shimo. They are made to float around and pummel each other before the gravity loss wears off and they fall into the access point that spits them toward the surface.
At this point the plot devolves into an insane tag team fight reminiscent of Godzilla vs Megalon. Little suko manages to take Kongs axe and shatter the crystal with it, evening the odds. 
Shimo freezes Skar King and then Kong takes one last look at him before slamming him into the deck shattering him into pieces. Godzilla fires a baby magic colored beam into the air, Kong roars, Suko chimps, Shimo looks on with gratitude.
Then we see Mothra repair the membrane protecting the Iwi tribe, Godzilla curls up inside the Roman Coliseum for a nap, Kong and suko and shimu announce to the Kongs that they are now free, Dr Andrews and Jia once again declare their unbreakable bond, and the credits start to roll... No post credit scene.
While this plot was a mess it was the most beautiful mess I have ever seen. I watched this in glorious real 3d and the eye popping special effects were as brilliant and effulgent as they were resplendent. I must admit I was put off by pink Godzilla (seriously what kind of Goofy shit is that) after the intense and horrific drama of Minus One but i am so glad i gave this movie a chance.
Five stars!!!