Abby and Caleb attended Whanganui High School together and both went on to study at the Whanganui School of Design.
They established their multi-media company, Lamp Studios, based upstairs in Victoria Ave, in 2012 and in 2015 they became parents to son Joseph.
Spending 12 days away from Joseph, who will stay with whanau in Whanganui while his parents are away, will be quite tough, says Abby.
"It will be the longest we've been apart from him since he was born."
She also feels a bit apprehensive that the Cambodian experience might make her feel a bit restless.
"We have always wanted to stay in Whanganui," says Abby.
"We made the decision that Lamp will sponsor one non-profit organisation each year, and we believe in helping in our own backyard first, but Flame has such a great philosophy and the work they do is sustainable.
"It is not just about going in and doing a bit before going away again."
Flame's work in Phnom Penh follows on from the Bong Paoun Project founded by French missionary Timothee Paton in 2009.
Education is seen as the key to changing the lives of families and Flame has reached more than 150 families living in seven Phnom Penh slums.
There are now 110 children attending school, with an additional 60 receiving study help and three football teams have been established.
A leadership programme is training 64 young people who have completed education to become mentors to younger students.
The charity has also assisted four families into self-employed work and many of the families are now receiving medical care that was unavailable before.
"We can help by shining a light on the work they do and encourage more sponsorship for them," says Abby.
"We chose the name Lamp for our company because our work is about recording things that need to be seen."
The Kingis will be housed and fed when they get to Cambodia, but they will cover all their travel costs through the company.
They will depart Whanganui on February 8 and return on February 21.