After being left behind by the Doctor, Sarah Jane Smith returned to her life as an investigative journalist. After seeing and experiencing so many wondrous things while traveling in the TARDIS, Sarah Jane still craved the adventure and excitement, so investigating alien and strange stories filled a need in her life. She continued her investigating for years until she found herself well into middle-age.

Over the years, Sarah Jane's life had become very solitary. She never took the time to have a family. There was always a new mystery to solve, never any time to get married and have kids. The secretive nature of her business was not conducive to close relationships.

So imagine her surprise when she suddenly found herself involved in the lives of a group of teenagers who also began involving themselves in her adventures. Without even noticing, Sarah Jane had finally found the family she missed out on.

Investigative journalist Sarah Jane Smith, with the help of her adopted son, his friends, and an intelligent supercomputer, continue to combat evil alien forces right here on Earth.