Isobel wanted to find a way to be a good person, so Kyle injected the serum into her. 

It was later revealed that Isobel did it herself but made Kyle think he did it. 

Her powers started to suppress, but then she started to fall apart, and he white blood cell count crashed. 

When there was no other hope, Liz and Michael realized that the only way to save her was to put her in the pod. 

The same pods that kept her and her siblings safe for many years. 

Noah struggled with everything that was going on and turned to smashing mirrors for excitement. 

Max got close to his mom again to try and find out more about the symbol, and she said that Michael was drawing it everywhere in his younger years. 

Michael made Maria a brand new sign that helped her mother find her way home, like a beacon of hope.