The Sun and the Star[a] is a 2023 American fantasy-adventure middle-grade fiction novel based on Greek-Roman classical mythology co-written by authors Rick Riordan and Mark Oshiro.

The story follows the adolescent demigods; boyfriends Nico di Angelo and Will Solace, the sons of Hades and Apollo, respectively, on their quest into Tartarus to rescue their old friend Bob, who is, in fact, the Titan Iapetus.

[5][f] Two months after the defeat of Nero and Python, Rachel Elizabeth Dare provides the prophecy for the adolescent demigods and boyfriends Nico di Angelo and Will Solace, the sons of Hades and Apollo, respectively, on their quest into Tartarus to rescue their old friend Bob who is in fact the Titan Iapetus.

Although the heist is successful, Will encounters Persephone herself, who offers advice on his struggles to understand Nico, suggesting that Will embraces his own inner darkness rather than rejecting it, before gifting Will the stolen pomegranates.

By combining their powers, Nico and Will free Bob before Nyx arrives with Nemesis, Hypnos, a reformed Epiales, and an army of monsters to cut off their escape.

Taking control of the cacodemons, Nico decides to release them, symbolically letting go of his demons and fulfilling the part of the prophecy that he would have to leave something of equal value behind.

As Bob sails the group back up the Acheron to the Underworld, Nico is visited in a dream by Hades and the spirits of his mother, Maria, and sister, Bianca.

Returning to Camp Half-Blood, Bob declines an invitation to stay and decides to head west to figure out his future, looking forward to finally having the freedom to do so.