Percy Jackson & the Olympians series, bk.3. When the goddess Artemis disappears while hunting a rare, ancient monster, a group of her followers joins Percy and his friends in an attempt to find and rescue her before the winter solstice when her influence is needed to sway the Olympian Council regarding the war with the Titans.

Jason, Piper, and Leo, three students from a school for "bad kids," find themselves at Camp Half-Blood, where they learn that they are demigods and begin a quest to free Hera, who has been imprisoned by Mother Earth herself.

When the god of thunder's hammer goes missing, Magnus Chase and his friends are tasked with retrieving it before an onslaught of giants attacks the mortal world.

The disappearance of the goddess Artemis while out hunting a rare, ancient monster, prompts a group of her followers to join Percy and his friends in an attempt to find and rescue her before the winter solstice, when her influence is needed to sway the Olympian Council regarding the war with the Titans.

"Magnus Chase, a once-homeless teen, is on a death-defying quest across the Norse realms, literally. As a resident of the Hotel Valhalla, this son of the god Frey is now one of Odin's chosen warriors. Magnus and his friends, Hearthstone the elf, Blitzen the dwarf, Samirah the Valkyrie, and other heroic characters must use all their wits and special talents in order to defeat fearsome giants, lethal creatures, and meddlesome gods in order stave off...

While Loki prepares his ship, Naglfar, to begin the final battle of Ragnarok, Magnus and his friends set sail to reach the vessel before it's ready, but angry sea gods and a fire-breathing dragon may prevent them from arriving in time.

When demonic cheerleaders invade his high school, Percy Jackson hurries to Camp Half Blood, from whence he and his demigod friends set out on a quest through the Labyrinth. Meanwhile the war between the Olympians and the evil Titan lord Kronos draws near.