Zarulium Chronicles IV: To the Rescue

Natalia, Joe, and Alejandro continue their search for Ruth, aided by the reformed Mantis. Complications occur afterwards when slight changes to the time continuum cause problems with memory loss and an altered sequence of events.

Dissatisfied that her Bermuda excursion did not include time for fun in the sun, Natalia convinces Joe to include himself in her next travel plans for the Mobile Time Machine, or 'Motimac' – as Joe has dubbed it. All does not go to plan while the pair of teens visits the Great Barrier Reef of Australia and Shuri Castle on Japan's Okinawa Island.

Meanwhile, a certain police constable has grown suspicious of Dr. Yakushev's 'activities' – but not as much as assassins continue to be baffled by them.

Eventually, a pair of 'off-world' rescues needs to happen as well, and all the while, an asteroid continues its menacing passage towards Earth.