Uncharted 2: Among Thieves is a 2009 action-adventure game developed by Naughty Dog and published by Sony Computer Entertainment. It is the second game in the Uncharted series and was released in October 2009 for PlayStation 3. Set two years after the events of Drake's Fortune (2007), the single-player story follows Nathan Drake, Chloe Frazer, and Elena Fisher as they search for the Cintamani Stone and Shambhala while battling a militia led by war criminal Zoran Lazarević. Development for Uncharted 2: Among Thieves began immediately following the critical and commercial success of the first entry. The development team drew inspiration from explorer Marco Polo and his expeditions through archipelagos and eastern Asia. Naughty Dog developed an updated proprietary engine for Uncharted 2: Among Thieves, which runs exclusively on the Naughty Engine 2.0 system. These improvements enabled extensive motion capture, greater in-game cinematic sequences, and inclusion of an online multiplayer component, a first for the franchise. Uncharted 2: Among Thieves received critical acclaim for its elaborate set pieces, character design, storytelling, graphics, technical innovation, and gameplay mechanics. It received Game of the Year accolades from numerous publications and award events and is considered to be one of the greatest video games ever made, and among the most significant titles for the seventh console generation. It also enjoyed great commercial success, with over six million copies sold worldwide. The game was followed by a sequel titled Uncharted 3: Drake's Deception in 2011, and was re-released on PlayStation 4 as part of Uncharted: The Nathan Drake Collection.