I thought the first episode of Signal was solid. I thought the second episode was fantastic. And then . . . well, then the show decided to go full throttle for “big emotional moments”. There were a lot of explosions, a lot of lurid cases, mostly involving ghastly things done to women, and a whole lot of crying. Despite excellent acting by Kim Hye Soo and Jo Jin Woong and stylish directing, I found myself becoming less and less engaged. Thrillers, especially those that dare to mess with the space-time continuum, demand top-notch writing, and while the script was serviceable, it never fully worked out the logistics of its crisscrossed universes. The actual detective work was also slighted, with its crack team instantly solving crimes that had baffled cops for years. Pinning all the blame for cases turning cold on “corruption” may be satisfying wish-fulfillment, but it felt lazy, especially in a show gunning for gritty realism. On the plus side, the show's fast pacing tends to paper over the plot holes, but it shortchanges the development of most of the secondary characters. They become “innocent victims” or “evil elites” we’re supposed to mourn or hate simply because of the suffering they endure or inflict on others. Occasionally there are glimpses of greater depth before the show bustles viewers off to the next crime scene, but I would have appreciated fewer set ups and more follow through. The concept is intriguing, but once you unwrap the layers of snazzy time warp packaging you’re left with a pretty ordinary procedural. The present may be able to change the past and vice versa, but the conventions of the crime drama survive unscathed.