Talk about it here.
After many failed attempts to make profit, the fortunes of the Slitheen waned. They were put out of business by the Blathereen, who were cheaper and more effective. In the year 2501, Ecktosca and Dram were imprisoned on Justicia. However their Aunt Callis broke into Justicia to rescue them. They helped the Ninth Doctor stop the Blathereen's plan to turn Justicia into a planet destroyer. After the death of Don Arco, they stole the surviving warp-hole technology to rebuild their fortune. (PROSE: The Monsters Inside)
Ecktosca Fel Fotch Heppen-Bar Slitheen and Dram Fel Fotch Heppen-Bar Slitheen were captured on Justicia. Callis Fel-Fotch Heppen-Bar Slitheen broke into Justicia to rescue Ecktosca and Dram. (PROSE: The Monsters Inside)