Clifford D. Simak’s 1976 Shakespeare’s Planet is a standalone SF novel.
Carter Horton wakes from hibernation to the news that his starship’s long voyage in search of an Earthlike world has finally succeeded. Unfortunately, this quest took a thousand years in the ship’s frame of reference and even more in Earth’s frame of reference. All of his human companions died in a mishap centuries ago. His only remaining companions are his Ship’s mind and an obsequious robot named Nicodemus.
Oh, and Ship refuses to head back to Earth on the grounds that enough time has passed to make their quest utterly pointless.
Horton soon discovers that the world Ship discovered was already inhabited. A horrifying appearing but quite amiable alien calling itself Carnivore appears to beg a ride off the planet. Carnivore’s mastery of the English language is unexpected, but there’s a sensible answer: the alien learned English from a fellow castaway, a human named Shakespeare.
Carnivore reached the planet via tunnel, an interstellar portal network set up who knows how long ago by builders unknown. The network is unreliable; nobody knows how its addressing system works, so destinations are more or less random. This world’s tunnel is even less user-friendly than most destinations: it only accepts incoming travellers. Once someone reaches the nameless world, they are stuck there until a ship arrives or until they die.
The robot Nicodemus does his best to repair the tunnel. No luck: not only is the technology far beyond human, the tunnel isn’t broken. The builders intended the world to be a trap. Of course, everyone could pile into Ship and leave, but since the hibernation systems are designed for human biology, poor Carnivore might spend the rest of his days waiting for the Ship to reach another world.
Another traveller, this one a woman named Elayne, arrives. She is one of a legion of pilgrims who are mapping out the tunnel network the hard way. Her latest jaunt brought her to Shakespeare’s Planet. Unfortunately her knowledge of the tunnels is not at all helpful in discovering a way out of this particular dead end.
While the group struggles to find a solution, they learn about other oddities of their prison.
For example, there is a pond nearby that seems to be alive. It communicates; it is curious about Horton and company. However, it isn’t clear whether it is friend or foe.
Once per day everyone on the planet (robot aside) is subjected to the God Hour, a disquieting psychic contact. Who or what is doing this is unclear.
The planet was inhabited at one point, but by whom is unclear.
Why they left is not known.
It does seem that the tunnel builders were trying to contain something, but what that something might be is unknown.
As is what the castaways should do should whatever it was that inspired the tunnel builders to seal off a whole world ever wakes up.
Shakespeare is not the Shakespeare. He was a terminally ill, mentally disturbed man who thought it the height of fun to spin wild lies to the naïve Carnivore while secretly mocking the alien.
This was not a great Simak novel. In fact, it’s a poor example of his craft. Among the many issues:
dodgy science, such as Simak’s curious insistence that nobody knows how time dilation works;
the two-dimensional nature of the characters, which means that the reader is not disposed to sympathize when they spend most of the book complaining about their captivity.
One question that is never satisfactorily resolved is what role Horton and his companions were supposed to play in the matter of finding new worlds: Ship handled the navigation and preliminary exploration, while Nicodemus has pretty much any skill one could want. Nicodemus thinks humans have some vague quality robots lack  but the text does not support this. Horton spends most of his time poking around ineffectually while grumping at the other characters. Arguably, it’s bold monster-hunter Carnivore who is the protagonist of the tale, in as much as Carnivore is the only character whose actions affect the plot’s outcome.
On a similar note, while Carnivore has a reasonable purpose in wandering the tunnels (he’s looking for monsters to test himself against), it’s not clear why mapping the tunnels requires Elayne and her compatriots to do it. By this point in human history, thinking machines are millennia old. A brute force approach involving millions of robot probes would probably get the job done much faster.
Still, there are some classic Simakian details amidst the gloom and the mutterings about the futility of existence. Chief among them is that with the singular exception of the Completely Evil Thing for which Shakespeare’s Planet is the prison, pretty much every thinking entity there is able to find common ground with every other thinking entity regardless of appearance, lack of common language or off-putting smell. And who knows: if they’d had the chance to talk to the Completely Evil Thing for any length of time, perhaps they’d have found some way to co-exist.
1: Nicodemus may be shading the truth here. Readers are told that Nicodemus was designed to put humans at ease. Early models were shiny and perfect and quite frank about their wonderfulness. Humans hated them.