Lyons was stuck in the trunk for hours as a group of people planned their next steps from inside a nearby disused water tank.
They wanted him to confess to child molestation, prosecutors told the jury on Thursday.
Lyons was eventually taken out of the boot and tied to a massage table, where he was tortured, before being locked inside the boot again.
The next time he felt the fresh air, Lyons was thrown into a shallow grave and shot.
Three months later, in March 2019, police were driven into dense bush, where they found his remains.
Jordan Bottom, Rikki Smith and Albert Thorn face trial in the Supreme Court, charged in the December 2018 death of Lyon.
All three are charged with murder, assault and unlawful imprisonment.
Bottom pleaded not guilty to all charges. Smith and Thorn pleaded guilty to intentionally causing injury, but deny murder, assault and imprisonment.
Prosecutor Raymond Gibson alleged the attack had been planned by Thorn and another man in the days prior.
Before arriving at Lyons’ home, Thorn visited a camping store and purchased two balaclavas and two rolls of duct tape to restrain the man, Gibson said.
He said Thorn arrived at the property just before 1 p.m., where he was later joined by Smith and two others.
The four men went to the back door of the house and headed for the master bedroom, where Lyons was recovering from a night of shift work.
“They then immediately attacked the unsuspecting Lyon who was lying on the bed,” Gibson told the jury.
“The men started attacking Lyons in earnest.”
After that, Lyons was thrown into the trunk of the car and taken to a rural estate where he was tortured.
Gibson alleged that Thorn, Bottom and Smith put him back in the boot and drove him to Double Bridges, where they placed him in a shallow grave and shot him in the leg and head, the killing.
“The three men buried Lyon and left the area,” he said.
Prosecution and defense submissions will continue on Friday at the trial before Judge Andrew Tinney.