Poseidon. Earth Shaker has Poseidon himself as its narrator and it tells stories of the god’s offspring and of his contest to be the patron of Athens. As a first generation Olympian, Poseidon was part of the overthrow of Cronos, and the graphic novel opens with the brothers Zeus, Poseidon, and Hades looking down into the great chasm into which Cronos has been hurled. The division of the realms takes place, and "of course" (p. 4), Poseidon receives the seas as his domain. There are many scenes of him swimming in the waters and churning them to thunderous whirlpools and waves with his trident. The waves can appear like horses galloping towards the shore and Poseidon can tower above ships that look like miniature toys beneath him.

Poseidon's first story is of Odysseus, who we see for the first time adrift in the sea. To Poseidon he is, "a creature of my niece, Athena" (p. 13) There is a red-backed scene of Odysseus at Troy in the thick of battle, a frame showing the Trojan Horse being led to the gates of Troy, one of Athena scattering the home-bound Greeks. The tale of Odysseus and the cyclops, Polyphemus, follows. Poseidon relates the story with insight into Odysseus' thoughts, but he also communicates his own perspective, conscious of the events' impact on "My son. Polyphemus" (p. 15). He includes Polyphemus' back story: Poseidon's affair with Polyphemus' mother, Thoösa, Polyphemus' disastrous love for the nymph Galatea. Poseidon hears his son's prayer against Odysseus and grants it. He notes that the cyclops is his son after all, "and my children have always tended to be monstrous (p.16)." His other offspring are shown: Triton, Otus and Ephialtes, and Pegasus. The discussion of the desire for children leads into Poseidon relating the myth of King Aegeas.

Aegeas travels to Delphi to learn how he may sire a son. He falls for Aethra in Troezen, but by night Aethra is visiting Poseidon in the seas. He hides a sword and sandals beneath a rock, leaving word that if Aethra's child should recover them he must visit Athens to claim Aegeas as his father. Aethra tells Theseus that he has is unnamed father's eyes. For the reader this confirms Poseidon as Theseus' father, yet Aethra shows the young man where to find Aegeus' tokens and he retrieves them and heads to Athens. Greater than Athens is Crete. Poseidon now relates the story of the bull he sent to King Minos from the sea. Poseidon was displeased by the king keeping the bull, and so inflamed a passion for the bull in the queen. Daedalus invented a mechanism through which the queen conceived a child with the bull, and the Minotaur was born. It is named Asterion, but the people call it Minotaur and Daedalus is punished for his part in its conception by being compelled to build a maze to house it in. Heracles travels to Crete and captures the bull, but once in Athens it escapes again, with Poseidon implying a hand in it. Aegeas is holding games at Marathon, and the bull kills Minos' son, who is attending.

A "grief-stricken" (p. 33) Minos invades in revenge and demands a nine-yearly tribute of fourteen young people. Theseus is accepted by Aegeas and he plans to travel to Crete. Beneath the waves, Poseidon hears as Theseus declares himself the son of Aegeas. Ariadne gives Theseus a sword and spool of thread, whispering that she senses that there is more to him than "just Aegeas's son, Theseus" (p. 37). There is a long sequence of combat and then Theseus stands triumphantly over the corpse of the Minotaur, with Poseidon's image rather than his own reflected in the pool of blood. Theseus brings the Minotaur's head out of the labyrinth, noting that it "barely defended himself" (p. 42). Ariadne grieves it and recalls the time in which her father tried to raise it as his child. Theseus takes Ariadne from Crete, but deliberately maroons her on Naxos. Theseus forgets Ariadne "just like that" (p. 44), and he forgets his promise to his father. Aegeas can be seen as a tiny speck falling into swelling seas, and "the sea claimed Aegeas" (p. 45). Theseus is decaled king of Athens, and Poseidon exults in having a son on the Athenian throne at last. Theseus looks knowingly out at the reader as Poseidon notes again, "my children have always tended to be monstrous" (p. 46). 

A new tale begins, the myth of Poseidon and Athena's contest to be Athens' major deity. Poseidon recaps who Athena is to him: he as there at her birth, she killed his granddaughter Pallas, and transformed his lover, Medusa, into a monster. Poseidon strikes the ground with his trident and a spring gushes forth. The people are initially ecstatic, but then quickly disappointed to find that it is salt-water. Athena calls forth the olive and wins the contest. Poseidon recalls bitterly that he also lost in contests to be deity of Argos, Corinth, and Aegina. He muses on why he rarely wins, and recalls the time Zeus was enchained by Athena Hera and himself, only for the Hekatonchieres to burst forth and rescue him. The resulting fight recalls to Poseidon's mind the battle of the gods when the Olympians overthrew Cronos. Rhea gave Cronos a foal when Poseidon was born, while Poseidon in horse form runs free with a herd. One day his world was pulled apart and he found himself first swimming, then standing in human form with his siblings before the fallen Cronos. His time with the herd is revealed to have been a dream-like sequence experience in the belly of Cronos, from which he is now free. He recalls again the division of the realms. We see him on his throne beneath the waves. 

The narrative is followed by an Author's Note in which O'Connor discusses the experience of writing a story focused on the elusive Poseidon. There are summary pages for Poseidon, the Minotaur, and Odysseus. G(r)eek Notes give further information on details in the text and images. For Discussion provides eight questions to support further consideration of the myths in the volume. There is a two part bibliography with recommendations for adults and children.

Poseidon. Earth Shaker is the fifth instalment of the Olympians series. In the Author's Note, O'Connor reveals that he re-wrote this novel several times, finding it difficult to express the elusive Poseidon adequately. A mainstay of the solution was to make Poseidon the narrator, which undoubtedly has the effect of revealing Poseidon's unique point of view and making the god more familiar. This may be felt particularly in the retelling of the creation myths. Readers of the series will by this volume be familiar with the events of Cronos' reign and the war of the gods, yet this story is refreshed by a retelling which centres Poseidon, notably in the way he bristles at Zeus' assumed leadership and not least in the hugely creative treatment of Poseidon's time in Cronos' belly. By rendering that time as a dream-like sequence in which Poseidon and others live as horses, this lesser-known area of Poseidon's dominion – his mastery of horses – is made deeply personal to him and unforgettable to a reader.

The decision to focus on Poseidon's children also creates the opportunity to retell familiar myths from an unfamiliar perspective. While readers will recognise the cyclops Polyphemus as the monster in the story of Odysseus, he becomes nonetheless a somewhat sympathetic figure in this retelling as the reader appreciates the over-step in Odysseus' actions and hears the narrator's concern for his son. The myth of Galatea (Ovid, Metamorphoses 13.738–788), briefly told, adds depth to Polyphemus' character and reads as a father describing their dysfunctional child. The retelling of his encounter with Odysseus paraphrases the account in the Odyssey (book 9) yet features something new with the alternate emphasis. The author takes care to provide readers with a brief backstory for Odysseus, enabling even those who are totally unfamiliar with Homeric epic to connect this story and Odysseus with the Trojan War. 

The myth of Theseus and the Minotaur follows. In the text notes, O'Connor names his debt to Patrice Kindl's 2002 Lost in the Labyrinth for his critical perspective on Theseus and for the charming and sympathetic detail of Ariadne recalling, "I used to put flowers on [the Minotaur's] horns" (p.43). This Theseus is explicitly Poseidon's son. This tradition is known from antiquity, though it was less frequently told than that in which he was the natural son of Aegeas (Plato, Republic 391c; Apollodorus 3.208; 3.216; Pausanias 1.17.3; with Plutarch, Theseus 6). Theseus is cold, impersonal and other-worldly; during what should be his most intimate moments, hugging his father or Ariadne, he is instead staring past them to the seas. Ariadne's fate appears bleak. She is last seen on the beach waiting so long that her clothes began to fall apart; there is no rescue from Dionysus and Theseus' abandonment of her is entirely deliberate. Unusually, however, this is not a result of apparent disinterest in Ariadne but an effective way of reinforcing the characterisation of Theseus as profoundly callous, "he had completely forgotten her; just like that." It is implied but not stated that Theseus deliberately failed to raise the white sail in order that Aegeas might somehow be removed from the throne, as indeed proves to be the case. As the handsome Theseus looks directly at the reader Poseidon repeats his line that "his children have always tended to be monstrous." This sends a chill down the spine and makes the neat point that some monstrosity is of form and some of morality; Theseus is a beautiful monster. In effect, although this is the story of Theseus and the Minotaur, it is told within the wider frame of Theseus' life; how he came to be born and become king. This enriches the story, as does the inclusion of some of the Minotaur's backstory through the inclusion of the Bull from the Sea narrative. The story is told with beautiful attention to detail regarding the Minoan environment. Walls and objects are adorned with iconography that is familiar from Minoan artefacts and frescos, particularly bulls' heads, double-axes, tiered dresses and dolphin imagery. The Minotaur looks ferocious but is ultimately a pathetic creature.

The myth of Poseidon and Athena's contest for Athens is told with good humour although the reader may find themselves feeling a degree of sympathy for Poseidon that this myth rarely evokes – a sympathy driven by the series' volume by volume focus on each Olympians' individual perspective. We are reminded of the various wrongs that Athena has done her uncle (Poseidon) over the years which strengthens both the sense of his displeasure in losing to her and the sense of the Olympians as a long-enduring dysfunctional family. Poseidon then reminds the reader of the various other patron contests that he lost, reinforcing the characterisation of the god as something of a malcontent whose power is best seen in his watery realm rather than on land. The many images of the god within the seas express his impressive power, the force of raging waters in storm and the uneasy peace of quiet seas. Similarly, the focus placed on Poseidon's offspring and their connections to the sea draws attention to the central importance of that element in a great many Greek myths. This is a dynamic treatment of Poseidon that urges readers to recognise his force and ambiguity.