The Nankai Trough Seismogenic Zone Experiment (NanTroSEIZE) program is a coordinated, multiexpedition drilling project designed to investigate fault mechanics and seismogenesis along subduction megathrusts through direct sampling, in situ measurements, and long-term monitoring in conjunction with allied laboratory and numerical modeling studies. The fundamental scientific objectives of the NanTroSEIZE drilling project include characterizing the nature of fault slip and strain accumulation, fault and wall rock composition, fault architecture, and state variables throughout the active plate boundary system. During Integrated Ocean Drilling Program (IODP) Expedition 338, drilling is planned to extend riser Hole C0002F, which was started during IODP Expedition 326 in 2010, from 856 to ~3600 meters below the seafloor (mbsf) over a 4 month period beginning in late September 2012 and ending in early January 2013. IODP Site C0002 is located in the Kumano forearc basin in the upper plate above the seismogenic, and presumably locked, portion of the plate boundary thrust system. The Kumano Basin sedimentary sequence and uppermost most part of the accretionary prism has been sampled and analyzed during IODP Expeditions 314 (logging while drilling [LWD] to 1401.5 mbsf) and 315 (coring to 1057 mbsf). The proposed extension would access the deep interior of the Miocene accretionary prism and would allow characterization of a unique tectonic environment that has never been sampled in situ by ocean drilling. The primary goals for Expedition 338 Site C0002 are riser drilling, analyses of cuttings and limited cores (100 m from 2300 to 2400 mbsf), LWD, and casing to the target depth of 3600 mbsf. This will allow addressing the primary scientific objectives such as (1) determining the composition, stratigraphy, and internal style of deformation of the Miocene accretionary complex; (2) reconstructing its thermal, diagenetic, and metamorphic history (3) determining orientation of minimal horizontal stress within the deep interior of the inner wedge; (4) investigating the mechanical state and behavior of the formation; and (5) showing how Objectives 1–4 relate to overall structural evolution of the Nankai accretionary prism and the current state of the upper plate above seismogenic plate boundary thrust. The hole is planned to be deepened during operations later in 2013. This Scientific Prospectus outlines the scientific rationale, objectives, and operational plans for drilling this site and contingency options.