Un hombre que ha sido sometido a un experimento se hace invisible y tiene la opción de ayudar a la gente sin que nadie lo descubra.

Goblin, también conocida en español como El guardián: El dios solitario y grande, ​ es una serie de televisión surcoreana de drama romántico y fantasía, transmitida por TVN desde el 2 de diciembre de 2016 hasta el 21 de enero de 2017, protagonizada por Gong Yoo, Kim Go-eun, Lee Dong Wook, Yoo In-na y Yook Sungjae.​​

British scientist Peter Brady, while working on an invisibility formula, suffers a tragic accident which turns himself invisible. Unfortunately, there is no antidote, so, while working on a method to regain his visibility, he undertakes missions for his government stopping bad guys.

Dr. Daniel Westin creates a formula to be used for matter transformation. To test the formula he uses it on himself. Before he can return to normal he discovers the government wants to use his formula for wrong, so he destroys it. Being unable to become visible again, he and his wife become agents for KLAE fighting crime.

Sam Casey is an agent for INTERSECT, a government think-tank and operations center specializing in secret missions. While on a diving assignment, Sam was affected by the radiation from an underwater explosion. The radiation rendered him invisible, but INTERSECT devised a way to control his invisibility, by fitting him with a computerized watch that kept him visible. He could, however, shut it off, and become invisible again, for short periods of time. If he did this for more than 15 minutes in any 24 hour period he would die. This ability to become invisible made him a very effective agent.