Reader beware - you're in for a scare!
Dr Brewer is doing a little plant-testing in his basement.  Nothing to worry about.  Harmless, really.
But Margaret and Casey Brewer are worried about their father.  Especially when they . . . meet . . . some of the plants he is growing down there.
Then they notice that their father is developing plantlike tendencies.  In fact, he is becoming distinctly weedy - and seedy.
Is it just part of their father's "harmless" experiment?  Or has the basement turned into another little shop of horrors?