"And Then There Were Four" is the 22nd episode in Season 4 of Lab Rats: Bionic Island. It first aired on January 13, 2016. This is the 94th episode overall.


Everyone is shocked when Douglas introduces a fourth bionic sibling named Daniel who’s been living a normal life with an adopted family.


Main Cast

Recurring Cast

Mentioned Cast


  • This episode show all 5 bionic siblings.
  • This is the last regular length episode of Lab Rats.
  • This is the first Lab Rats episode to air in 2016.
  • This episode airs exactly two years after No Going Back.
  • Chase's siblings never invited him to his 16th birthday party. This is similar to what happened to Leo in Bionic Birthday Fail. However, not inviting Chase was intentional.
  • The title could possibly be a reference to the And Then There Were None book/film.
  • A new bionic sibling is revealed in this episode named Daniel.
  • This episode shows that the Lab Rats had kept many lies from each other.
  • A new bionic ability called Power Replication is revealed in this episode.
    • So far, Daniel is the only bionic person to have this ability.
  • It is revealed that Leo had a iguana named Iggy, only for it to be killed by Donald. This is similar to how in Mission: Space, Leo said Marcus was probably killing his hamster.
    • This implies Leo has had many pets in his life.


  • Leo is shown in an orange (advanced level) training outfit. However, in Lab Rats: On The Edge, he was promoted to mentor.
    • Though this could be because of when the episodes were filmed.


Lab Rats 'Gallery'
The image gallery for And Then There Were Four may be viewed here.





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