Template:Infobox Lost Character-1 Desmond David Hume is a recurring fictional character on the ABC television series Lost played by Henry Ian Cusick.

Template:Spoiler Desmond David Hume is a man who was living in the DHARMA Initiative research station -- the Swan -- under the mysterious hatch.

He had previously served in Her Majesty's Army, dishonorably discharged for refusing to follow orders. He served a prison sentence which kept him away from his love, Penny Widmore. The book he kept in prison was Our Mutual Friend by Charles Dickens. After his release, Penny's father bribed/threatened him to stay away from his daughter.

He crossed paths with Jack years before being stranded on the island when both men were running the stairs of an empty stadium at night. The two have a brief but meaningful conversation, in which Desmond explains that he is training for a race around the world, a race sponspored by Penny's father. Desmond gets the boat from Libby, who acquired it when her husband David died. During the race, Desmond's racing ship crashed on the island, and a man named Kelvin Inman emerged from the jungle and took him back to the hatch. Desmond watched as Kelvin input the numbers into a computer. When Desmond asked, "What was all that about?" Kelvin replied, "Just saving the world".

Kelvin trained Desmond about operation of the hatch, including the button and ways to trigger a lockdown. We see Kelvin painting a blacklight picture on the bulkhead doors. Desmond confronted Kelvin after learning that Kelvin was fixing Desmond's boat and planning to leave the island. After Kelvin expressed his doubts about the validity of pressing the button, they struggled, and Kelvin died. Desmond raced back to the hatch, where the computer was registering a system failure. A massive magnetic field was building up, attracting all metal objects to the sealed door inside the hatch. Desmond managed to stop the system failure, which turned off the magnetic field.

One day, Desmond hears someone shouting from the top of the hatch. It is Locke asking for help, and as Desmond turns on the light Locke quiets down as he feels his pleas have been answered.

When the survivors enter the hatch, they accidentally break the computer. Convinced that the world is going to end, Desmond frantically flees the hatch. Jack catches up with him; Desmond tells him the code, and to enter it every 108 minutes. As he begins to recognize Jack from their encounter at the stadium, he asks him about the patient he had mentioned operating on. He is refering to Sarah, whom he later married, and eventually divorced, and this reminder brings Jack to tears. Desmond then exits with his backpack, filled with items such as unknown vaccines and a stuffed bunny, saying, "See you in another life, yeah?" just like he did before at their first encounter at the stadium.

Desmond returns in his boat, the Elizabeth, at the end of season 2, and Locke tells him of the orientation film he saw in the Pearl hatch. Together they trigger another lockdown, trapping Eko outside the computer room, and wait for the countdown to hit zero, sure that nothing will happen. Eko uses dynamite from the Black Rock to attempt to get back into the computer room but fails.

As the countdown reaches zero, Desmond realizes that the date of the prior "system failure" was the same day as the plane crash, September 22nd, 2004. Desmond believes that this magnetic field is what pulled down Oceanic flight 815, and that his failure to press the button is the same as the date of the plane crash. He is insistent that the button must be pressed, but Locke reacts by destroying the computer monitor (presumably disabling the computer as well). Desmond retrieves a key that Kelvin had shown him could "end it all." He says "See you in another life, brother" to Locke and uses the key to "blow the dam." As he does so, a giant white light envelops the island. The fate of Desmond (as well as Locke and Eko) is uncertain, although it is certainly conceivable that he is dead.

We see a Portugese magnetic research station notice the magnetic anomaly. They put in a call to a woman revealed to be Penny Widmore.

• "Man of Science, Man of Faith"
• "Adrift"
• "Orientation"
• "Live Together, Die Alone: Part 1"
• "Live Together, Die Alone: Part 2"