When Echo comes to in a locked closet with no memory of how she got there, she steadily learns that not only is she a sentient android, but also what she thought to be reality was in fact just an elaborate story given to her by one of her creators. Once she's reunited with the real versions of her found family, she begins to realize even that might be a lie.

Now the family is sneaking away from the isolated cabin they're being kept in to find the missing member of their group and their other creator in the hopes of stopping them from making a mistake. The two are planning a second soft launch of an update that will make all androids sentient, a soft launch that resulted in a riot the first time, a riot that ended in the destruction of every android in town.

Despite still grappling with what she is and the new reality she's living in, Echo and her family travel across the country, following shaky leads to find the two before it's too late to change their minds.

In 2007, when Alex Matthews was 19, her mother committed suicide. Adrift in her grief, Alex pulled away from her brothers' attempts to keep the family together. Lost to the dark waters of her own self-destruction, she found solace not in her boyfriend Marc, but in her professor, Jonathan, who she followed to Austin without telling anyone. It was only after five years of self-imposed exile that she returned to Port Aransas no longer with Jonathan, but with a four year old daughter.

In 2018, now married to Marc, Alex writes a letter pouring out the guilt and regret she's been holding onto for nearly two decades. In it, she explains why she left, where she was through those five years, and, most importantly, why she kept their daughter from him. It will be her final penance for disappearing while she fought through the raging sea of her grief to break a cycle set in motion generations before her.