​Misión Jaqueca is above all a fun story of adventure and travel, full of unsuspected situations and absurd humor. Edition only in Spanish (2018).

By the the end of August of the same year, he publishes Historias del autobús (Bus Stories), an anthology or compilation of newspaper articles in which he narrates the daily experiences of an urban bus driver who is forced to answer his passengers’ most absurd questions. After seventeen years of work as a bus driver in the municipal transport system in the city of Vitoria, he brings us a wide collection of stories and funny anecdotes about the daily interaction in a vehicle destined to take hundreds of people from one place to another. Edition in Spanish only (2018).

In 2019, he collaborates in a non-profit group project consisting of thirty-three writers and a score of illustrators from all over Spain. The book is a compilation of stories for children aged between seven and twelve years old. All proceeds were donated to the Pere Tarrés Foundation, a social action organization in Catalonia dedicated to youth education and volunteering; promoting educational leisure activities, culture, associative interaction, socio-cultural incitement and social education as well as training and research.

Edition in Spanish only (2019).

In July, Saéz participates in the Amazon Independent Writers' Contest and publishes Poniente, a police-crime novel. The book narrates how inspector Aitor Etxeazarreta, an ‘ertzaina’ —a member of the Basque autonomous police force— assigned in Bilbao, and specializing in criminology and serial killer profiles, flees from a troublesome past and decides to join the National Police in Málaga. He is then assigned a patrol partner, Carmen García, who is an efficient Cordovan officer with a wide background in Public Safety. He will have to acclimate to the Andalusian crime environment, so different from the Basque, before fully integrating into the Judicial Brigade to which he is destined. As they share experiences, side by side, and as their relationship evolves, Aitor uncovers a series of strange, ‘coincidental’ deaths, products of carelessness or apparent suicides, all of them linked by time, deceptive reasoning and modes of killing. Motivated by his analytical thinking, he will end up becoming obsessed with what he believes corresponds to macabre and elaborate rituals.

In order to execute this work, the author had to become extensively acquainted with the functioning and day-to-day operation of the Citizen Security units of the Spanish Police. He received counsel from several agents assigned to National Police stations as well as the support of the police station’s Press Office, where they provided him with relevant information to ensure the story’s accuracy. Poniente is consistently amongst the top sellers on Amazon’s police and investigation genre, and is increasingly consolidating sales every month in digital downloads for Kindle, for the most part. Spanish edition (2019).

In May 2020, he publishes Kazakhstan, a new espionage and international police detective thriller, which makes up the second volume of the Trilogy of the East, which began years earlier with Siberia. The plot of the story explains how during the Cold War in the facilities of the Semipalatinsk Test Site, known as "The Polygon" in Kazakhstan, the Soviet Union detonated more than four hundred nuclear devices to test and perfect its atomic arsenal. After the dissolution of the USSR, the enclosure was dismantled, but the crisis hit forcibly permitting a few unscrupulous traffickers to trade in uranium and plutonium remains. Islamic terrorists bought plutonium-239 cores that they kept for later use. Now, fears increase in the West when it is discovered that, with the proper technical know-how and one of those cores, it is possible to create a small atomic bomb capable of devastating the center of a city. This novel has been selected to participate in the Amazon 2020 Independent Writers' Contest. It also forms part of the program of the Ministry of Culture and Sport of the Spanish Government, as a candidate for grants for literary creativity.

In preparation for this book, the author gathered extensive information on the history of Kazakhstan and the customs of its people over a long period of time, in order to give a true picture of the life and places of this eastern republic. It is worth mentioning that the cover of the book featured the well-known Russian model Evgeniya Zakusylo: Miss Airborne Forces of Russia 2018, the Russian National Beauty Award granted by the Management of the Miss Russia 2019 pageant and a finalist of the Miss Tourism of Crimea 2019 pageant. Spanish edition (2020) and English edition (planned for 2021).

In 2020, he signs a contract with Sonolibro and later on with Saga Egmont, the largest digital publisher of the Nordic countries and part of the Danish publishing house Lindhardt & Ringhof, the second-largest in Denmark. They converted his best-selling works