Foothills of Zane Lagoon

Seven teen Cousins, the Stiles-Tracy brothers, Tyson, James, Jason, the Zane Twin sisters, Sammy and Tammy and the Cupp brothers Dev and Mel meet for the first time at Zane Lagoon.  Deceived by Great Aunt Rosie Zane on the pretense of celebrating her 75th birthday, to be there visiting for the summer only, when in reality they are there at Zane Manor for a whole year.  So that she can decide who gets the Zane fortune when she dies.  Or is this her only reason to have her 5 grandnephews, and her Twin third cousins there.  The Zane legacy is a family tree going back to 1900 where there is a Cupp married to Benjimen Zane the first Lumber Baron of Zane Lagoon.
 His son marries a Stiles, and his grandson marries a Smith.  A Smith future descendant marries a Cupp future descendant, and their son marries a niece of Rosie Zane.  Another niece of Rosie Zane marries a future descendant of a Stiles.  That future is here, 2025 and the seven cousins sort out the family tree and discover a mystery.  It is not the only thing they sort out.  The Stiles-Tracy brothers 17, 16, 15 have issues.  Their mother widowed twice, and the younger brother comes out Gay.  The Twin sisters 15, their father married twice are identical twins but have different traits and personalities, that conflicts as twins.
 Our Cupp brothers 15 and 14 appear to be your average siblings but are they?  In the Foothills of Zane Lagoon, they not only discover personal growth to overcome their issues.  They, discover a 105-year-old mystery together that saves 3 billion lives.