9 From the Nine Worlds

This collection of nine interconnected short stories is a companion to Rick Riordan's Magnus Chase and the Gods of Asgard trilogy, set in a version of Norse mythology where the Nine Worlds of the cosmic tree Yggdrasil coexist alongside the modern human world. The stories share a connecting thread: Thor, the god of thunder, is jogging through all Nine Worlds to log 10 million steps on a fitness tracker called a FitnessKnut, hoping to earn a cameo on a television show. His oblivious passage through each realm causes complications for the other characters.

In the first story, set in Asgard (the realm of the gods), Odin, the All-Father and king of the Aesir gods, deals with a Valkyrie food fight in Hotel Valhalla, the eternal home of the einherjar, warriors chosen to train for Ragnarok, the prophesied end of the world. Since the death of their captain Gunilla, the Valkyries have grown unruly, and Odin reviews candidates for a new captain. The final candidate claims to be Hladgunnr, a former Valkyrie, but begins to shape-shift, an ability the real Hladgunnr lacked. The imposter is Utgard-Loki, king of the mountain giants, who infiltrated Asgard while Heimdall, guardian of the Bifrost (the Rainbow Bridge), was distracted filming a baby-goat video. Utgard-Loki escapes using distortion magic. Humiliated, Odin disguises himself as a woman in chain mail to live undercover among the Valkyries and choose a captain personally.

The second story takes place in Midgard (the human world), narrated by Amir Fadlan, a mortal engaged to Samirah al-Abbas, a Valkyrie who serves as Odin's agent for special assignments. Amir visits Blitzen's Best, a Boston clothing store owned by his dwarf friend Blitzen, to buy an outfit for Sam's grandparents' anniversary party. Blitzen is absent, and a salesman named Stan tricks Amir into wearing nábrók, necropants made from an ancestor's skin that are bound by a dark-magic spell generating endless gold coins. The cursed trousers cannot be removed. Alex Fierro, a gender-fluid einherji (a warrior who lives and trains in Valhalla) and Sam's half-sibling, discovers Stan's deception and alerts Sam. Sam arrives in Valkyrie armor, and together she and Alex overpower Stan, destroy the dark-magic spell with Sam's light-magic spear, and slash the necropants off Amir. Amir donates the gold coins to the Chase Space, a shelter for homeless children run by their mutual friend Magnus Chase, the einherji protagonist of the broader trilogy.

In the third story, set in Nidavellir (the underground world of the dwarves), Blitzen stumbles into a tavern while fleeing an old rival. There he finds the severed but magically preserved head of Mimir, an ancient god, who warns that a dwarf named Alviss plans to ambush Thor. Thor once petrified Alviss to prevent him from marrying Thor's daughter, and Alviss seeks revenge. Blitzen must stop the attack without alerting Thor, whose rage could endanger all dwarves. Since petrification requires sunlight, which the underground realm lacks, Blitzen crafts a handheld tanning bed that shoots a concentrated sunbeam. At the ambush site, he trips Thor just as Alviss swings down from the ceiling with a club, causing the attack to miss. Blitzen then petrifies Alviss with the device. Thor jogs on, oblivious.

The fourth story follows Hearthstone, a deaf elf and rune mage, in Alfheim (the realm of the light elves). A bracelet from Inge, a hulder (woodland sprite) Hearthstone once freed from his family's enslavement, signals that she is in danger. He tracks the signal to a mansion guarded by former police elves and a massive troll. After exhausting his rune magic in combat, Hearthstone recalls that speaking a troll's true name breaks its defenses. He feigns helplessness, exploiting the troll's vanity until the troll reveals its name: Siersgrunnr. Using a megaphone and his dagaz rune, which converts sign language into spoken words, Hearthstone broadcasts the name and defeats the weakened troll. The mansion's occupants release Inge, and Hearthstone reunites with her.

In the fifth story, Odin sends Sam to Jotunheim (the realm of the giants) to photograph the egg of Fialar, one of three roosters whose crowing will signal Ragnarok. A skyscraper-tall giant named Eggther guards the nest, sitting on the egg while playing a self-playing golden harp. When Eggther falls asleep, Sam rigs a vine to steal the harp and lure him away, but Thor barrels through and catches his foot on the rope, yanking the harp free. The harp plays an alarm, Eggther chases after Thor, and Sam photographs the uncracked egg before returning to Asgard.

The sixth story sends T.J. (Thomas Jefferson Jr.), an einherji and son of the war god Tyr, to Helheim (the realm of the dishonorable dead). The goddess Hel shows T.J. a vision of his long-dead mother in chains and threatens to torture her unless T.J. lures the escaped hellhound Garm back to its cave. Because T.J. carries Tyr's blood, Garm can smell him, making T.J. ideal bait. T.J. encounters the ghost of Balder, a god slain by a mistletoe arrow. Knowing mistletoe is poisonous, T.J. borrows the arrow and jams it down Garm's throat after a fierce struggle. The poison incapacitates the hound, which collapses in its cave. Hel later assures T.J. in a dream that his mother is safe.

In the seventh story, Mallory Keen, an einherji, accidentally exits Hotel Valhalla through a random door into Niflheim (the world of ice and mist). Stranded in a blizzard, she follows a trail Thor has melted through the snow until it disappears, then tracks the sound of water to Hvergelmir, the hot spring at Yggdrasil's roots. She encounters Nidhogg, the dragon that gnaws on the World Tree and wages an eternal insult war with an eagle in the treetops. Mallory trades classic schoolyard retorts for safe passage and climbs the tree back to Valhalla.

The eighth story follows Halfborn Gunderson, a berserker einherji and Mallory's boyfriend, to Vanaheim (the realm of the Vanir gods) to collect dragon scales for a secret mosaic he is crafting as a gift for Mallory. The Vanir dragons sleep peacefully, but Thor stampedes through and kicks them awake. Halfborn goes berserk, kills all four dragons, and collects scales from their bodies. He reassures the horrified Vanaheim warriors that the mythical creatures will eventually be reborn.

The final full story follows Alex Fierro to Muspellheim (the world of fire giants). Magnus's sentient sword, Jack, alerts Alex that Surt, the fire lord, is recruiting forgotten minor gods to fight at Ragnarok. Alex goes alone because Surt can detect einherjar, elves, dwarves, and Valkyries, but Alex's shape-shifting makes her harder to identify. She crafts a fire-protection membrane, infiltrates Surt's palace as a series of insects, and resists his hypnotic voice. Disguised as a gnat, she whispers doubts into each deity's ear, sowing dissent. When Surt grows suspicious, Alex stings him inside his tiny nose as a bee, then overpowers him with her garrotte and his own sword. The minor deities vanish. Alex's friends arrive after being alerted through the underground weapon network, a gossip chain among magical weapons. Blitzen ties Surt up, and Alex warns the fire lord that they will be ready if he plots against them again.

A brief epilogue, narrated by Thor, reveals that his epic jog across all Nine Worlds was for nothing: He forgot to turn on his FitnessKnut.