Continuing from the last arc, Thor is now aware that Thanos is teamed up with Mangog, and they are, together, ending life on planets as part of Thanos’ quest for the love of Death. Note that Thanos isn’t really into Death anymore, so this is later retconned to be part of a group of cloned Thanoses–called Thanosi.
He’s not clearly fake in this story.
Thor and a Rigellian Recorder travel through space where Thor pursues Thanosi and Mangog, joined by Firelord who is looking more fiery than he used to.
Thanosi is gathering “stones’ that aren’t the Infinity Stones and much of this story has lots of posing and statements of big cosmic import. In other words, there’s lots of filler. Thor keeps arriving at the planet where Thanos is supposed to be, only to find the planet in ruins and Thanos gone.
Meanwhile, there’s some Asgard drama where Balder has convince a troll to start making Asgardian weapons, while Odin watches Thor’s adventures in space via the equivalent of intergalactic magical CNN.
Eventually Thor catches up to the villains and hammers Mangog in the face.
Repeatedly.
Odin gets the magical Asgard weapons to Thor via Firelord and beats the snot out of (not) Thanos, killing him. The battle is appropriately epic.
There’s not much story. There’s lots of big fighting pictures.
After winning the battle, the story turns to New York City, showing us Titania in the hospital without health insurance, dying. I’m hoping that means next issue Thor takes his hammer and beats up Blue Cross/Blue Shield.