Bashir and O'Brien enter the mind of a dying Sloan to find the Section 31 cure that could save Odo.
With Odo near death from the Changeling disease, Bashir spreads word of a false cure to lure Section 31 to the station. He captures Luther Sloan, who triggers a device to destroy his own brain rather than be questioned. Bashir and O'Brien link their minds to Sloan's in a race to find the cure before he dies, risking death themselves.
Inside Sloan's mind they confront versions of him, are fooled by a false return to the station, and finally reach his office full of Section 31 secrets. O'Brien stops Bashir from lingering over them, and they escape with the formula just in time. Bashir uses it to cure Odo.