Chuaigh long chogaidh Haileabó, An tAonbheannach, go tóin poill agus ciste luachmhar ar bord. Nuair a thagann Tintin ar mhacasamhail na loinge sin, aimsíonn sé leid faoin áit a ndeachaigh an long síos sa Mhuir Chairib. An féidir teacht ar an gciste — más ann dó i gcónaí?

His ship, the Aonbheannach, was lost to the deep along with the pirate’s booty, but when Tintin finds a model of the warship, a clue appears which could lead to the treasure’s location… will Tintin be able to decipher the mystery?