The paper analyzes a lightning storm on Saturn that raged for 7.5 months at a planetocentric latitude of 35 deg. south from 27 November 2007 until 15 July 2008. The storm system produced about 277000 lightning events termed SEDs (for Saturn Electrostatic Discharges) that were detected by the Cassini RPWS (Radio and Plasma Wave Science) instrument. The SEDs are organized in episodes, lasting typically for half a Saturn rotation. SEDs can be detected when the observer Cassini is within the radio horizon (usually when the storm and Cassini are on the same side of the planet), and they are not detected when Cassini is beyond the radio horizon (Cassini and the storm on opposite sides). Saturn's atmospheric storm features have a much higher angular velocity than Cassini around Saturn, so that one SED episode is typically related to one Saturn rotation. The SEDs from this storm, lasting from the end of Nov. 2007 until mid-July 2008 (termed storm F), occurred in 439 SED episodes.