Episode 18 of "Elementary" Season 4 recap for "Ready or Not" reveals Sherlock and Joan's mission to locate Dr. Vincent Bader. Those who were not able to watch the latest episode may find out what happened to their task below.

Before anything else, here's the official synopsis for Episode 18, "Ready or Not" per CBS, as quoted by Hidden Remote. The previous episode can be viewed via their website as well.

"When a survivalist doctor goes missing, Holmes and Watson must determine whether he's purposely gone off the grid or if he's a victim of foul play. Also, Holmes exhibits odd behavior when his romantic relationship with Fiona hits a critical point."

Going deeper to the plot, TV Fanatic catches some of the most important part of it. As the website wrote, they are trying to locate the missing doctor because of the fact he is to blame for Brian's addiction to painkillers.

As the search commenced, Dr. Bader's spouse revealed that her husband is a "devoted prepper,' a survivalist preparing for the inevitable apocalypse." The information became vital for the duo.

More than that, his colleague, Dr. Wallace, also claimed that he was selling drugs to a gang as a part of his practice. But an "auditing" scare made him quit and promised that he will never deal with the sources ever.

The search was successful but the doctor was already dead as they have guessed that he is killed by a "survivalist" who uses different and innovative tools. It turned out the the victim has been trying to steal "The Keep's" drugs to continue his practice but was unsuccessful.

Meanwhile, Sherlock and Joan's relationship has been on the rocks, that the girl proposed a sex to the former. What will happen on their flair? It will be revealed soon.

"Elementary" Season 4 episode 19 will be aired on Sunday, April 3, 10 PM EST on CBS.