Overgrowth is the most recent horror novel written by Mira Grant (Seanan Mcguire's pen name for this genre), published by Daphne Press. A romp, fun, but also thought-provoking sci-fi horror, a character driven story set against the backdrop of an alien invasion, using the horror genre to explore themes such as the othering of minorities with the pretext of the common well-being.

Stasia Miller walked off into the woods one day when she was three years old and had an encounter with an interesting plant; after coming back from that encounter, she's been telling everyone that she's an alien, vanguard to the invention that will happen, even if not many people believe her. Thirty-two years later, Anastasia is an adult and has a boyfriend; however, an alien message has been received and people start to suddenly notice what Stasia was saying, as the threat of an alien invasion only brings more uncertainty as the days pass.

With this backdrop, we have an interesting proposal that looks at humanity, found family and choices; the signal acts as the spark for the story. Despite having that compulsion to say she's an alien for years, Stasia can't be sure how the encounter with her alien family will go, but when she's persecuted by her own government, stripped of the rights she should have (due to her alien origin), it will be proved that she can only trust in those friends that are her found family. Grant puts a great care on creating a cast that stays with you in the middle of the chaos of the story, even if the villains are a little plain/stereotypical (especially the agent).
Pun not intended, but also the growth of Stasia as character is another of the highlights of the book, especially after her encounter with her real family.

Overgrowth is definitely not afraid of going for creepy and eerie moments, gifting us some moments that are nightmare worthy; the alien invasion also gives us an insight into how quickly a society can devolve into fascism in the name of protecting its citizens. While the alien invasion is not a new trope, I liked how Grant approached to it, giving it a fresh touch. 
In terms of pacing, I really enjoyed the beginning and the ending, but it is true that it can slog a bit in the middle section, especially as we are introduced to Stasia's adult life; but overall, it is still enjoyable, as all those details drop in that section will eventually make sense.

Overgrowth is an interesting sci-fi horror novel, perfect if you are looking for a book that could be described as Little Shop of Horrors meets Independence Day, thought-provoking but with a fair dose of action. If you liked her previous horror novels (honestly, I still love Feed), I totally recommend you to give this one a try!