Thrive by Kenneth Oppel

Thrive is the final installment in the Bloom trilogy opening where the second book left off. A cryptogen ship has just been shot down by the Canadian military. From the vessel three cryptogens emerge; a flyer with dazzling golden wings, a swimmer and a runner. All the cryptogens are wearing special masks to help them breathe, as Earth's environment is still somewhat toxic to them. After Anaya convinces both sides to stand down, the cryptogens are brought inside. 

Seth has also returned to Deadman's Island. He fills Petra and Anaya in on what happened to him and Esta when they were left behind: Sienna was captured by police,  how Darren stung Seth with his tail causing Esta to force him to jump from the boat after blasting him with sound and how the marine police captured Esta from the boat.

The three rebel cryptogens have been placed into the Vancouver Aquarium's biodome, now "a cryptogenic landscape of high black grass, berry-laden  vines snaking  from buried pit plants, and seed-spitting water lilies floating serenely on a pond so acidic no human would dare swim in it..." The cryptogen ship has also been moved into the biodome. 

Colonel Pearson has Anaya, Petra and Seth communicate with the cryptogens so they can learn what they are planning. Terra, the rebel cryptogen, explains to Anaya that there are not many rebels aboard their vessel of over seven hundred thousand aliens which is now orbiting Earth. She also reveals that there were ten rebel landings on the planet but refuses to reveal the locations of the other landings. Terra tells Anaya that they need to extract the code from the hybrid's blood to make a chemical weapon and that the final invasion is planned in a little over a month so they need to move fast. Once the weapon is made, it can be taken back to the alien ship and released there. This will allow the rebels to gain control of the ship, overwhelm the flyers who are in command and leave, preventing the invasion.

In Petra's communications with her cryptogen, she can't sense the alien's gender and decides to use the pronouns ze and zir (in a nod to the current gender ideology fad). She learns that the swimmer is a scientist who took part in creating the human hybrids and that there are thousands of hybrids on Earth. The swimmer tells Petra that they created the hybrids because they needed them as a safe place to keep the "substance" and also as translators.

As Seth communicates with the flyer, whom he calls the general, he is shown the battle on the cryptogen's planet in which the runner and swimmers are destroyed by the sonic blasts from the flyers. The general was wounded but tended to by runners who saved his life. This experience changed how he viewed the swimmers and runners. When those who treated him were all killed he was disgusted by what had happened and became a spy for the rebel cryptogens. The general was responsible for starting the rains on Earth that led to the changes in the ecosystem and to the human hybrids. He tells Seth that the rebels have come to form an alliance with the humans and fight against the invasion. He also tells Seth that they hid a code inside of the hybrids and they now need it. The code is to make a virus which will permanently destroy the flyers ability to use sound as a weapon. Seth also learns that he will never achieve his dream of flying as his body is too heavy.

Later that day, over dinner, Anaya reveals that Terra told her they can repair their damaged ship's hull but the levitation system is damaged. There is however a ship that crashed sixteen years ago when they first came to Earth, and if they can locate it, they might be able to salvage the part.  

Seth continues to be focused on helping Esta, who Dr. Weber reveals is being held in a detention center in the U.S. She is accused of murdering Dr. Ritter. When Seth protests that she's innocent and that he killed Ritter, Dr. Weber tells him he's considered an accessory to the murder. When Seth expresses his determination to find Esta, Dr. Weber promises to ask Colonel Pearson where she's being held.

Pearson arrives and reveals to the group that intelligence has discovered that at least two ships, one over North Korea and another over the Suez Canal have been shot down. Pearson refuses to tell the Americans anything, for fear of jeopardizing their ability to make the weapon. 

The next day Terra takes Anaya inside their ship to extract what they need from her body to make their weapon. While they are working on making the virus into a weapon, Terra works on locating the crashed cryptogen ship in the hopes they can use its levitation device for their own ship. The crash site turns out to be located in northeastern British Columbia, in a swamp, with the ship underwater. To recover the levitation device, Petra and the swimmer are flown out to the site in a helicopter. But the retrieval proves to be daunting as Petra and the swimmer must fight off giant squids while the helicopter is almost taken down by giant parasitic creatures.

Meanwhile Seth has learned that Esta is being detained at Point Roberts. This leads him to sneak away from the aquarium to rescue her, but he only succeeds in getting himself captured and back into the hands of the cruel Dr. Ritter who it turns out has survived. Back at the base, Terra, with the help of Anaya and Dr. Weber is successful in creating a virus that affects the flyers' ability to use their sound weapon. But are they too late?

The early arrival of the cryptogen invasion force throws all their plans into chaos. As the cryptogens attack new plans are needed if they are to use their weapon on the flyers and give the rebel cryptogens and Earth a chance.

Discussion

Thrive is a fitting conclusion to Kenneth Oppel's Bloom trilogy about human's overcoming an alien invasion. In this series,  the story focuses on a group of human-alien hybrids, bred by a rebel alien faction, determined to thwart their planet's colonization of Earth. The novel is filled with character-driven action scenes including an epic battle between humans, hybrids, rebel cryptogens and the invading cryptogens. The ending is predictable and upbeat, with a final battle between the cryptogens, rebels, hybrids and humans.

Thrive is arguably the weakest of the three novels, with the events almost anti-climatic. Readers know the humans will prevail in the end. And after so many gruesome creatures in the first two books, any new ones the humans encounter seem almost expected. But in Thrive, the three main characters, Anaya, Petra and Seth, finally come into their own, each facing their own fears and challenges. This is especially true of Petra and Seth. 

In Thrive, Petra steps up to do her part to help out. Initially she has been reluctant, still struggling to accept the physiological changes she's experiencing and wanting her old life and her human body back. But with the help of the swimmer and as the situation becomes more dire, Petra rises to the challenge, helping in the recovery of the levitation device, saving the swimmer's life, devising a way to spread the viral weapon when the rebel's plan falls apart, and attempting to rescue the trapped hybrids on the cryptogen ship over Point Roberts.

Seth also commits himself. Abandoned by his mother, Seth has struggled to belong, and is now forced to choose who he will fight for; humans or cryptogens. The commander of the cryptogens tells him the human hybrids were mean to inherit the new earth and that they will thrive in it. He is also told he will fly, something he has dreamed of all his life. But this doesn't fit with what Terra has told them back in the biodome. Unlike Esta, Seth notes the difference in the way the commander and Terra have presented what is happening and he's not sure who he can trust. He also has, in the back of his mind, "the general's sonic message...wanting to be opened." From this message, Seth learns the truth about the cryptogen commander and her intentions for the hybrids. He also learns that he must finally make a choice, a painful one because he learns the truth about the one person he has come to identify with but who is a traitor.

For Esta, there is only one choice, solidarity with the cryptogens. On the cryptogen ship, Seth, Esta, Darren and Siena are given accounts of what happened on the cryptogen's planet that are much different from what Terra has told Anaya . While Esta accepts what she is being told, Charles counters, "Even if we don't know whose story is true...we know one thing for sure. These guys are here to take over our planet. That does not make them the good guys. Are you okay with everyone dying but us?" After the general and the swimmer rebels are captured and killed by the cryptogen flyer commander, Esta tells her fellow hybrids they have to make a choice. She tells them the choice is obvious because the cryptogens are going to win, meaning the hybrids will be safe. And so she acts on what she believes.

Thrive is an exciting read, with lots of battles, gruesome creatures, evil cryptogens and human traitors. Young readers will enjoy the satisfying ending, in what is one of Oppel's best offerings to date.

Book Details:

Thrive by Kenneth Oppel
Toronto: HarperCollins Publishers Inc.  2021
405 pp.