Six Gates from Limbo

Three travellers find six very different worlds await their choice - if they have the courage to leave Eden...
On awakening in an idyllic tropical paradise, Rex is disoriented and possibly afflicted with amnesia. He knows his name, but the particulars are curiously missing. He spends his first week exploring, and discovers that his Eden-like paradise is surrounded by a huge unscalable wall 50 miles in circumference. Furthermore, there are six gateways at roughly equal intervals, but there is no way to climb up there and see where they go...