The dual timelines were fun and I liked that they pretty much ran the same path 35 years apart. The speculative elements were fun, though I thought it was a missed opportunity they weren't more "helpful" to Viv or Carly. The supporting characters were well fleshed out and I think they added a lot to the story, especially Nick, Heather & Alma. All in all it was a great mystery and really kept me guessing.