This month, Jeff and Anna Dowley will take on the Mystery Box Rally that departs on August 22 from Townsville - a part of Australia the Dowleys have not yet explored.

The rally’s objective is simple: to drive a car worth no more than $1000 across some of Australia’s roughest dirt roads, all in the name of charity.

Seventy-five duos carry enough food and petrol to last the 2500-kilometre, five-day trip with only a vague itinerary of each day’s destination.

‘‘That’s the fun part about it,’’ Mrs Dowley said.

‘‘It’s a proper road trip but you’re not in control of it.’’

Established in 2013, the Mystery Box Rally is the little brother of the Shitbox Rally, which was founded in 2010.

To date the Shitbox Rally has raised more than $6.1 million and the Mystery Box $432,000.

Together the two events, held in different locations each year, have raised more than $6.5 million for the Cancer Council.

All funds stay with the Cancer Council, however, with the money they raise teams ‘bid’ on their mystery cars the night before the rally.

This is the second year the Dowleys have entered the rally as team Panda Dropbears.

The cause is one close to their hearts as they have both lost family members to cancer.

Last year they raised $4777 and bid on an ‘88 Ford Fairlane, which survived the Brisbane rally with only a loose transmission wire.

With less than three weeks to go until the Townsville rally, the Dowleys have raised more than $3000 through events and donations.

■ To support team Panda Dropbears, go to Everyday Hero and search 'Panda Dropbears'.