The Secret of the Kloog - The Altar of Shulaani, #3

Mike's father goes missing on a remote island. Mike, Alinea and their alien pet Beeper travel through a time gate to retrieve him. Finding him unconscious, they have to protect him. But first they have to escape being dumped once more at the Intergalactic Lost Property. After that, they jump the usual hurdles: illegal dealers that want them silenced, and staying far away from Kloogs forever raiding the protected planets.
An odd creature, the Quok, that Beeper distrusts is the only one prepared to help them. However, when they arrive on the mysterious 'Place of the Call', they realize Beeper's distrust of the Quok is terrifyingly well-founded...