Castle's lost time has been a giant failure. The first attempt to answer it was very underwhelming and nonsensical, and now this new spin isn't much better except to tie every plot together. It was clear that cliffhanger was written for shock value without any idea as to how to resolve it.
The issue was I think that was show runner group A or B and now they are on show runner group D or E. So every time there is a change there is a new spin and no one plans it out.
Beckett should just be running for the Senate to explain her not being in episodes. I could write better shows that the few I have seen.