A plot to attack Canadian buildings and politicians was an unrealistic "jihadi fantasy," hidden from a 20-year-old man on trial for his role in the alleged terrorist conspiracy, his lawyer said Thursday.

In closing remarks, defense lawyer Mitchell Chernovsky said the prosecution had failed to prove its allegations that his client was a participant in a genuine terrorist cell. The defendant, a Canadian, has not been identified because he was 17, a legal minor, at the time his 2006 arrest.

He was one of 18 people arrested for allegedly plotting to attack Parliament buildings, behead politicians and truck-bomb nuclear power plants and police headquarters.

He pleaded not guilty to terrorism-related charges, including aiding a terrorist group by shoplifting camping supplies and walkie-talkies.

He is the first of 11 people to face trial. Charges against the seven others arrested have been withdrawn or stayed.

While the group's leader, who the accused saw as a mentor, vowed to "cripple Canada" and began recruiting people to implement his scheme, even the prosecution's star witness testified the man was little more than a self-aggrandizing braggart.

"He lied about everyone and everything," Chernovsky told Superior Court Justice John Sproat. "One wonders if he was even capable of telling the truth."

Even if the man did have genuinely nefarious ideas, his "complete ineptitude" precluded anything from ever happening, the lawyer said.

"All of this is a fantasy, an illusion, with zero probability of ever being implemented," Chernovsky said.

The prosecution argued that the accused was an enthusiastic participant in camps intended as preparation for the terrorist attacks.

However, Chernovsky noted t-hat even the prosecution's own star witness testified the accused was unaware of the alleged plot.