How did it end?

Unfortunately, it didn't. Tessa's investigations about her father's murder didn't seem to progress in the second half of the series. The last episode had Montoya proclaiming the martial law, which may have turned out to be a very dangerous development, but Tessa uses Vera to convince Grisham to destroy the document. Vera continues her relationship with Grisham even if she knows he's previously drugged her (we'll never know if anything has changed between them to some degree- Elsa Pataky doesn't exactly possess the acting subtlety to make the final look she gives him remotely telling..), Dr. Helm makes it clear that he's in love with the Queen (they would've ended up together had the show progressed) and every other character stands exactly where he did at the beginning. Final conversation between Tessa and Marta precisely states that everything's back to normal.