Castle Season 7 Premiere
Castle Season 7 airs every Monday on ABC. Castle/Facebook

Castle Season 7 returns tonight with episode 3 titled 'Clear & Present Danger' and Rick Castle and Kate Beckett will investigate the case of the 'invisible killer'.

Rick went missing in the premiere episode of ABC's crime investigation drama only to be found after two months but with erased memories.

This awkward kidnapping has left the mystery novelist puzzled and now he is seeking all the answers which are nothing short of a riddle.

In the second episode Alexis tells Castle that the '38' number key found in the lining of his pants, is actually for a safe deposit box in the Montreal Bank. In the bank he discovers envelopes with memory cards in it with the addresses of Kate, Martha and Alexis.

The synopsis of episode 3 'Clear & Present Danger' reads:

"When a pool shark is murdered by an unseen force, Castle and Becket uncover evidence that the killer may have paranormal powers. Meanwhile, Castle and Beckett attempt to get their lives back to normal following his disappearance."

The episode will also focus on the much-longed romance by fans as Caskett will attempt to bring back the sizzling romance in their life.

Cartermatt suspects that the duo may consummate their love in the third episode.

It will be interesting to see how the celebrated writer's intuition and Beckett's creative detective work will solve the case of the 'invisible murderer.'

Castle, Season 7 episode 3 'Clear & Present Danger,' airs tonight (13 October) on ABC.

Click here to watch the episode live stream online for free on ABC's official website.