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Invisible Cap in Percy Jackson and the Olympians: The Ultimate Guide

Annabeth's Invisible Cap is a magical item that had the ability to make the person who wears it invisible. It was a gift from her mother, Athena.


During a field trip visit to Olympus with some other campers including Luke Castellan, Annabeth's mother and the goddess of wisdom and war, Athena, gave it to her for her twelfth birthday. This is one of the only gifts that her mother has ever given her.

In The Mark of Athena, the magic cap had its magical properties removed after Annabeth Chase got into an argument with Minerva, her mother's Roman side. However, in The Staff of Serapis, the cap's magical properties were restored by Athena.


Annabeth using her cap to turn invisible.

The cap is similar to Hades' Helm of Darkness. However, it does not have any fear inducing properties, it cannot change its shape, and it does not make the wearer intangible.

In battle, or in any circumstance as a demigod, the hat is very useful. When worn, it makes the user and any item they're holding invisible. That in and of itself would make it very powerful, as its usefulness of stealth is an important and useful factor in battle and ingenuity on Annabeth's part makes it invaluable. Unfortunately the cap lost its magic in The Mark of Athena after Annabeth get in an argument with Minerva, her mother's Roman form. In The Staff of Serapis, Athena restores the cap's power and sends it to her daughter to help her defeat Serapis.

In The Crown of Ptolemy the cap is ineffective against Setne who is able to see through its magic and render it ineffective when Annabeth is wearing it. However, Egyptian magician Carter Kane is later able to use the cap effectively against Setne with it being wielded by a Egyptian magician rather than a Greek demigod making it an effective weapon against Setne.

Percy Jackson and the Olympians

The Lightning Thief

Annabeth uses the cap several times throughout the book, including to listen in on Percy's meeting about the Quest for the Master Bolt and during Capture the Flag.

The Sea of Monsters

Annabeth uses the cap to keep an eye on Percy in secret before later using it to defeat the Laistrygonians. when they attack Percy and Tyson.

Later, Hermes includes it in the duffle bags that he packs for the three for their quest and Annabeth uses it to sneak around onboard the Princess Andromeda. While in the Sea of Monsters, Annabeth uses it to trick Polyphemus. However, she loses it when Polyphemus manages to catch her. While fleeing from the evil Cyclops, Grover Underwood retrieves the cap for her from the ground.

The Titan's Curse

When Annabeth is abducted during the fight with the Manticore at Westover Hall, she loses her cap and it is recovered by Percy from the snow. Percy keeps the cap and uses it to eavesdrop on Atlas and Luke.

The Battle of the Labyrinth

Annabeth uses the cap to escape from Mount Saint Helens

The Last Olympian

Annabeth uses it to fight alongside Percy.

The Heroes of Olympus

The Mark of Athena

Following Annabeth's argument with Minerva, her mother's Roman side, the goddess revokes the cap's magical powers. Despite this, Annabeth brings the cap with her aboard the Argo II and tries it on every morning in the hopes that its magic will work again without success.

Demigods & Magicians

The Staff of Serapis

During the battle with Serapis, Athena unexpectedly returns the cap to Annabeth with its magical powers restored in order to help defeat the hybrid god. Annabeth is surprised to find the cap in her bag as she hasn't carried it with her for some time due to the cap's magical powers being gone. Annabeth realizes that Athena sent her some help and it both encourages her and worries her that the situation is so bad that Athena got involved herself, meaning that Serapis must be a real threat to the gods. Annabeth is able to use the cap to sneak up on Serapis' Staff and kill it, destroying the hybrid god.

After the battle, Annabeth plays with the cap and thinks about why Athena had given it back to her with its magic restored. Annabeth feels like Athena seems to be sending her a message: "there will always be threats too powerful to face head-on. You are not done with stealth. You must tread carefully here."

The Crown of Ptolemy

The cap proves to be useless against Setne who is able to see right through its power when Annabeth is wearing it. As a result, Annabeth later lends the cap to Egyptian magician Carter Kane, theorizing that as Carter would be an Egyptian magician using a Greek item rather than a Greek demigod using a Greek item, it would work better for him. The cap proves highly effective in Carter's hands, rendering him invisible to Setne and allowing Carter to launch a sneak attack that cuts off Setne's hand and recovers the Book of Thoth. In Carter's possession, Percy is unable to see him when Carter is invisible, even using the enhanced senses of Nekhbet whom he is hosting and he only becomes visible when Setne briefly goads Carter into revealing himself and attacking again with the Fist of Horus.


  • Annabeth Chase – The cap belongs to Annabeth, and was given to her by her mother Athena. The cap helped cause many victories and success in Annabeth's and Percy's quests.
  • Percy Jackson – When Annabeth was abducted in The Titan's Curse, Percy kept the cap and used it to eavesdrop on Atlas and Luke. Six months later, he used it to sneak up on Kronos before he could reform, as well as checking in on Nico di Angelo as he spotted him spying on the Hunters during Phoebe's outbreak of Hives caused by centaur blood, and accidentally startled Nico as he took it off. He also used it briefly in The Lightning Thief and The Battle of the Labyrinth.
  • Carter Kane - In order to defeat the evil ghost magician Setne, Annabeth gives Carter her cap, believing that while it didn't work for her against Setne, with a magician wielding it instead of a demigod, it might work. The cap proves highly effective for Carter who is able to sneak up on Setne and cut off his hand, allowing them to retrieve the Book of Thoth and saving Percy, Annabeth, and Sadie Kane's lives.


  • In ancient myths, Athena gave Perseus a helmet that turned him invisible. During the series, Annabeth, a daughter of Athena, has offered to let Percy Jackson use it on multiple occasions.  
  • In her official picture, Annabeth has the hat on and is seen starting to turn invisible from the bottom up.
  • Annabeth does not let anyone else other than Percy and Carter use the hat.
  • Percy actually had Annabeth's hat when she went missing in The Titan's Curse.
  • The cap seems to have a different level of efficiency depending on the type of wielder: against Setne while wielded by the demigod Annabeth, it was completely ineffective. However, when the magician Carter Kane wielded it against the same opponent, it was extremely effective to the point that even when hosting the goddess Nekhbet, Percy couldn't see Carter even with her enhanced vision.
  • The cap works similar to a Swan Cloak (notably used by Samirah al-Abbas) which can also turn the wearer invisible. Though unlike the cap, the cloak can hide up to two people.
Personal Weapons: Riptide | Annabeth's Knife | Backbiter | Frank's Spear | Hazel's Spatha | Katoptris | Nico's Sword | Thalia's Spear | Aegis | Hades' Sword | Kronos' Scythe | Ivlivs | Master Bolt | Poseidon's Trident | Reyna's Spear | Silver Bow | Hades' Staff | Juno's Gladius | Annabeth's Sword | Sumarbrander | Gungnir | Gjallar | Mjolnir | Thor's Staff | Khopesh | Mallory's Serrated Knives | Meg's Twin Imperial Gold siccae blades | Caduceus | Apollo's Golden Bow | Artemis' Knives | Ares' Sword | Ares' Shield | Thyrsus | Hecate's Torches | Minotaur's Axe | Leroy's Sword | Tyson's Javelin | Alex's Garrote Wire | Piper's Sword
Magical Items: Annabeth's Yankees Cap | Helm of Darkness | Keys of Hades | Flying Chariot | Golden Apple | Apples of Immortality | Greek Fire | Hermes' Multivitamins | Leo's Magical Toolbelt | Nectar and Ambrosia | Pandora's Pithos | Winged Shoes | Golden Fleece | Stygian Ice Whistle | Serapis' Staff | Magic 8 Ball | Arrow of Dodona | Pig Ball | Mechanical Spider | Angel Statues | Athena Parthenos | Chiron's Wheelchair | Diocletian's Scepter | Flaming Dodgeball | Gleipnir | Poseidon's Pearls | Queen Hippolyta's Belt | Mistletoe Arrow | Frank's Stick | Expand-o-Duck | Caligula's Caligae | Ran’s Net | Rune Stones | Nábrók
Spoils of War: Minotaur's Horn | Medusa's Head | Kampê's Scimitars | Nemean Lion's Pelt | Gorgon Blood | Cornucopia | Lydian Drakon Hide | Phineas' Robe and Slippers | Triptolemus's Almanac | Odysseus' Astrolabe
Items: Camp Necklace | Chameleon Armor | Daedalus' Laptop | Golden drachma | Denarius | Red Gold | Mark of Athena | Thalia's Shield | Video Shield | Wristwatch Shield | Golden Mango | Sibylline Books | Letter of Recommendation
Ships Amos' Boat | Argo II | CSS Birmingham | Egyptian Queen | Julia Drusilla Yachts | Pax | Queen Anne's Revenge | Reed Boat | Naglfar
Blessed Metals: Adamantine | Celestial Bronze | Imperial Gold | Stygian Iron | Bone Steel