La espada del tiempo (Magnus Chase y los dioses de Asgard 1)

First installment of Rick Riordan's new and thrilling adventure trilogy:
"Magnus Chase and the Gods of Asgard," based on Norse mythology.

The Viking gods have awakened.
Magnus holds the secret that can stop the end of the world.
But that same secret can also destroy him.

Magnus Chase has always been a troubled kid, living alone on the streets
of Boston, dodging both police and thieves. One day, a new shadow joins
his pursuers: his mysterious and until then unknown uncle Randolph, who
reveals an impossible secret to him: Magnus is actually the son of a
Norse god. Viking myths are real. The gods of Asgard are preparing for
the Great War. Trolls, giants, and horrendous creatures are training
for Ragnarok, the end of the world.

With the help of Sam, a Valkyrie who secretly hates him, and the dwarf
Blitzen and the elf Hearthstone, both fugitives, Magnus will travel
through the nine worlds in search of the only weapon that can stop
Ragnarok: a legendary sword lost thousands of years ago... And along
the way he will have to make the most difficult of decisions. Because
sometimes, to save oneself, it is necessary to die.

Readers' opinions:
"Forget everything you thought you knew about Norse mythology that Marvel
has taught us with its movies about Thor and Loki: Riordan is going to
give us a masterful class. And morbid."
Blog Talisman Dream

"Rick Riordan has done it again, with his new book, he has amazed me
again. Norse gods in a young adult book, with a protagonist who makes
you laugh out loud? Yes, please. [...] I'm eager to read its second
part now."
Blog Another Book

"My God, I'm in love with this book, both inside and out. Please, what a
marvel! How this man writes!"
Blog El olor a libro nuevo

"Rick Riordan surprises again and this time he does it with the
beginning of a trilogy based on Norse mythology, with a lot of action,
a lot of humor, a lot of adventures and fantastic characters, each in
their own way. I'm sure it won't disappoint his fans and will fascinate
all those who haven't yet ventured into one of his books."
Blog En un rincón de la estantería

"Once you start you can't stop because you need more, more, more, more.
It's a heart-stopping book. [...] A very good, spectacular, dazzling,
overwhelming start [to a trilogy]... It has everything."
Blog Ciudad de los libros

"The Sword of Summer is another masterpiece by Rick Riordan. With a
protagonist who will make you burst out laughing, a story with a fast
pace and an ending that foreshadows an even better second part, it's a
book I highly recommend."
Blog Within Books