They ran twice around the island, clocking more than 300km in the process.
All to raise $100,000 for an initiative that provides support for prison inmates and their loved ones.
It's no easy task. The Angel Tree initiative aims to reconcile ex-offenders with their families.
And some of these ex-offenders have gone in and out of prison repeatedly. People like Mr Isaac Lee Thiam Liew and Mr Jensen Lee.
Having spent years in prison for a variety of offences, both men said they were moved when their families turned up on the day they were released. They had reconciled with their families while in prison.
ANGRY YOUNG MAN
A shy child growing up around Boon Lay in the 1960s and 70s, Mr Isaac Lee, now 50, would get into fights with people because he felt uncomfortable that they were staring at him.
Then he was introduced to drugs. "Because I was shy, I felt that taking the tablets would help me to be more brave, then I could go out and even socialise with more people," he said in Mandarin.
It was this taste for drugs and violence that landed Mr Isaac Lee in prison five times: Thrice for drugs and once each for theft and for fighting.
He was last imprisoned in 2007 for consuming and trafficking "Ice", the street name for methamphetamine.
That was when his life took a turn.