The Doctor's physical and psychological battle for survival after being gravely injured by the antimatter surge/toxicity, and the frantic efforts by Sarah Jane Smith to rescue him.

Sorenson and Salamar's argument over the positron canisters masks a deeper betrayal as Sarah slips away. While Vishinsky declares the Doctor irretrievably lost, Sarah's growing desperation leads her into the …

With the escape vessel already lifting off, Sarah stumbles upon the Doctor near the rock pool where he has been collecting his vital positron samples. He is barely conscious, clutching …