The Locke-family is now partways arrived in Lovecraft and hope that their lives will normalize now, but the presence of Zack makes this wish nearly unfullfillable. And the key-house itself, of course. While his bigger siblings try to connect with their new age-mates Bode runs about the house with a new key whose function isn't all to apparent for him.
When he finally gets to the solution it causes a lot of distress in his siblings minds and lures Zack into the house, who finds a lot of clandestine and nefarous uses for it.
A successful continuation of the first part, with very engaging art by Mr. Rodriguez that stays with you long after you closed the covers.