The Last Guardian's story follows that of a boy who is trying to escape from a setting resembling the ruins of a large expansive castle. The game will revolve around the developing friendship between the boy and a giant, feathered creature resembling a griffin named Trico (トリコ Toriko?). The name of the creature can be taken to mean "prisoner" (虜 toriko?), "baby bird" (鳥の子 tori no ko?), or a portmanteau of "bird" (鳥 tori?) and "cat" (猫 neko?). Trico has spears and arrows stuck in its back, and is initially bound by a chain. Later, it is freed and is shown attacking an armored soldier. Screenshots, along with the E3 trailer, show the boy attempting to sneak past and attack other soldiers.[11] Trico will at first be hostile toward the boy, but during the course of the game, the two will develop an emotional attachment to each other. Ueda suggested there may be similar creatures like Trico in the game, but could not confirm this.
Some speculated, based on the tone of the 2009 E3 trailer and of Team Ico's past games, that The Last Guardian will end sadly; both Penny Arcade and Zero Punctuation postulated the ending of the game would involve the death of either the boy or Trico. In response to these theories, creator Fumito Ueda addressed them by stating the story is "open-ended, and for you guys to figure out."