Dennis Ryland (Peter Coyote) was the original supervisor of NTAC, the federal agency created to investigate and oversee The 4400. Dennis was promoted to deputy director of NTAC and moved to Washington, D.C., leaving Nina Jarvis in charge. He soon returned, though, to oversee the investigation of the disease afflicting The 4400.
But it was later revealed that Ryland was, in fact, the mastermind behind The 4400's illnesses. His experiments aimed to control The 4400's abilities by inhibiting the production of promicin. He was arrested after his involvement was uncovered by Tom Baldwin and Diana Skouris.
Tom and Diana are horrified to learn that Ryland knew about the risks and causalities involved with taking promicin and yet did nothing to warn anyone. But Ryland remains confident that if Collier allows causalities, maybe the public will no longer view him as a messiah. In an effort to regain his promicin supply, Ryland has Isabelle interrogate Shawn (who's in custody at NTAC) and together they try and hunt down Collier and the promicin. But when Shawn's information leads to a dead end, Isabelle decides it's time to make Collier come to her. How? By taking down the 4400 Center. Although Ryland tries to stop her, he is no match for Isabelle. Ryland finally realizes no one can control Isabelle, especially him.
Ryland is approached by Tom and Diana who urge him to seek protection from the newly free NOVA group. But Ryland explains that he has nothing to worry about, especially now that he has Isabelle on his side. Together, Ryland and Isabelle work with scientists to prepare their enhanced army for a suspected attack by Collier and the 4400. But what Ryland doesn't know is that the threat of an attack is merely a diversion, one that allows Collier the opportunity to steal Ryland's entire supply for promicin. With his secret weapon gone, Ryland wonders what Jordan is truly capable of.
Dennis Ryland is accused by Tom and Diana of running a secret program where soldiers are injected with promicin. His goal? To create an army with 4400 abilities. Although Ryland admits to nothing, his behavior clearly suggests that he is, in fact, conducting experiments. But before Tom and Diana can reveal the truth, Ryland makes a preemptive strike, announcing on-air the existence of his Enhanced Soldier program.
After a full recovery, Dennis Ryland now works as an Executive at Haspel Corporation, a company hired by the government to research the NOVA group. Ryland is unapologetic when Haspel Corp takes Alana into custody (after she confesses to tipping of Navarro) but when Tom agrees to trade Gary for Alana, Ryland agrees. Although the trade doesn't go down as planned, Ryland has more important things on his plate. Ryland and Haspel Corp have been conducting experiments on Isabelle.
On trial for the promicin inhibitor experiments, Dennis Ryland is attacked by his lawyer, who is being controlled by TJ Kim, a member of the radical NOVA group.
While recovering, a second member of NOVA, Gary Navarro, attempts to murder Ryland but is again unsuccessful.
SEASONS ONE AND TWO TIMELINE
When The 4400 land in Ryland's "backyard," the NTAC supervisor has the returnees quarantined. After six weeks of testing, research and consternation over what to do with The 4400, Ryland releases them back into society.
Ryland and the overbearing Agent Lytell track down Tom and Kyle Baldwin at Highland Beach. They find the two entranced by a white beam of light. Lytell, after being repelled by the light, shoots at Kyle, releasing the entity trapped inside him.
Ryland, since being relocated to NTAC headquarters in Washington, D.C., returns to take over the Pacific Northwest operations after Nina Jarvis is shot and wounded.
In an effort to control The 4400's, Ryland authorizes injections of the promicin inhibitor as a way to keep their powers in check. As a result, The 4400s fall ill and Ryland orders the returnees -- sick or not -- into quarantine.
Much to Ryland's dismay, Tom and Diana discover his complicity in the 4400 plan. When Tom confronts Ryland, Dennis blackmails his old friend by revealing that he knows about Kyle murdering Jordan Collier. But Kyle agrees to confess to the murder, freeing Tom to expose Ryland and NTAC's role in the scandal.
Ryland is arrested and charged with the murder of 23 4400s who died due to the promicin inhibitor.