Zara Zara , also known as Joy for a period , was a Tracer in human form . Biography . Zara was created by the Grace , powerful beings who created the Key to Time , to prevent the completion of the Key . Like her twin sister , Amy , she existed to find the segments of the Key to Time . ( AUDIO : " The Judgement of Isskar " ) During her journey , Zara was taken prisoner with the Seventh Doctor ' s companion Ace on the planet of Erratoon . She escaped with the help of Harmonious 14 Zink . ( AUDIO : " The Prisoner ' s Dilemma " ) Zara and Zink would encounter the Fifth Doctor and , her twin sister , Amy on the planet Mars . Zara would soon cause the collapse of the Martian society after finding a segment of the Key to Time . ( AUDIO : " The Judgement of Isskar " ) After being freed by the Grace , Zara made her way to the " Sphere " . On the " Sphere " , Zara met Marek , who got her pregnant . Abby , formerly Amy , followed Zara to bring her back to Pargrave , a soldier whom Zara had fallen in love with . They used their powers to earn enough money to escape from the Sphere . However , in a rage , Abby destroyed the Sphere . ( AUDIO : " The Sphere " ) After escaping the Sphere , they were taken into custody and accused of killing the loved ones of the people from a mysterious village called Compton . During an escape attempt Zara was left behind in their jail cell . Zara was threatened with death until the angry mob believed that Abby was also killed . Abby escaped and found herself slightly outside of the village only a week into the future and the village destroyed . It turned out that Compton was destroyed by a meteor strike , and that the tracer twins had arrived the moment that the meteor hit . The people in the village were echoes of the dead , and Abby and Zara escaped before they were destroyed by the meteor . ( AUDIO : " The Fog " ) When they escaped the village , Zara and Abby were captured by Marek , who used time technology to escape the Sphere before it ' s destruction . While in flight , they were captured by Kreekpolt . Kreekpolt wanted to use the twins powers to heal his daughter , who was fatal ill , but they were unable to do so . However , they suggested they go to the Grace , who would have the power to do it . At gunpoint , they were led to the Chaos Pool . When they arrived , the Grace granted the tracer twins immortality , and they could only die when they wanted to . After this , Abby , Zara and Marek departed from the Chaos Pool , hoping to start a new life together , raising the baby when it is born . ( AUDIO : " The End " ) She tried to seduce Manchu Golding in order to get her and her sister out of prison . She and Abby changed time to make a city survived being killed . She lost Marek and her daughter in the process . ( AUDIO : " The Line " ) She got annoyed that her action left a loss of information . She ran away and went missing . ( AUDIO : " The Flood " ) She didn ' t mind sharing Marek until she realised she loved him . ( AUDIO : " The Dark " ) She lost her mind when she fell through the vortex , but Abby helped her get it back . She went to go find Albert when there was a fire . ( AUDIO : " The Edge " ) She told Chi what they tried to do in the search for Marek . ( AUDIO : " The Battle " ) Abby convinced her to go back to the the Archive . There she was arrested for murder . ( AUDIO : " The Archive " ) She came and saw Brondle and Wing where she met Marek again . ( AUDIO : " Consequences " )