Ada is a friend of Happy's who, due to her compromised immune system, must live in a sterilized bubble.
Not much is known about Ada's early life, although when talking to Happy she claims she finds mechanics and physics interesting. She was diagnosed with an immunodeficiency brought on by aplastic anemia 3 years ago, causing her to have bad reactions to anything that is not entirely bacteria-free. Her father built an autoclave bubble to help her survive in a sterile environment, she is not able to exit the bubble.
Ada's already difficult life is put on the line when a power-line collapses in a severe storm, falling through the roof of her father's house, compromising her bubble. Happy, who was on the way to find Ada, is stopped by the situation and asks a nearby fireman what has happened. Happy then discovers that Ada's lack of response to the online female mechanics chat was caused by this incident, and calls in the team for help.
The team struggle to remove the debris from the bubble, as it gradually becomes more threatening in puncturing the bubble. With the help of Happy, the team resort to placing Ada in a temporary fire apparatus suit and taking her to a sterilized walk-in freezer at a restaurant nearby. On the way to the restaurant, Ada has a bad reaction and her breathing becomes slow and unstable. Toby points out this is not normal and she has little over 10 minutes to live if the team don't get her out of the suit. Knowing that she should be placed in a sealed, sterilized environment, Walter comes up with a quick solution; coating her in honey for the remainder of the journey while still allowing her to breath. When they arrive at the bee honey store, Ada sees light with her own eyes for the first time in almost 3 years. Happy spots this touching moment, realizing how difficult it must be (and is) for her to live with the rare disease.
When arriving at the freezer, she is moved into the freezer which needs to be burnt in order for the room to be sterilized completely. At this moment, the crew watch through video feed to ensure she is safe while the fire burns off. Happy then asks Ada a question to make sure she is okay, asking her a mechanical question. Although Ada doesn't respond immediately, with the team waiting anxiously, Ada emerges from the drum of honey, and answers the question - Happy smiles.
At the very end of the episode, Walter passes on a handmade VR headset to Ada's father, that was once intended for Tim and Paige, allowing Ada to experience the prom in virtual reality while inside the freezer. Toby, acting as Ada's self, gives Ada the experience of dancing with Sylvester. Walter assures her that he will find her a bone marrow donor, stating that he has formulated an algorithm which finds all valid donors, and it will never be impossible, even it takes up to 18 months.