Abstract: A retrievable well tool which can be lowered into a well casing and set on a wire line and thereafter moved for resetting or retrieval with a drill string. The tool includes a body having expandable slips mounted thereabout for anchoring with the casing. Drag blocks which are longitudinally slidable along the body slide from a first to a second position to expand the slips. A lug on the drag blocks is received into a channel on the body. Manipulation of the plug body effects locking the drag blocks into their first position. Shear bolts maintain the drag blocks in their first position when the tool is initially lowered into the casing on a wire line. A shiftable abutment adjacent the drag blocks is selectively operated to shear the bolts and shift the drag blocks to their second position to anchor the tool.