Children’s and YA sequels hitting shelves this month include the ninth installment of a bestselling middle grade graphic history series, a fictional spy memoir set at the 1989 Video Game World Championships, the story of a dog contemplating his name, and more.

The Invisible Leash: A Story Celebrating Love After the Loss of a Pet

by Patrice Karst, illus. by Joanne Lew-Vriethoff (Little, Brown, Dec. 3, $17.99, ISBN 978-0-316-52485-8)

This grief-focused picture book serves as a companion to The Invisible String, Karst’s rumination on how love connects family members even in absence. When Zack’s dog dies, Zack’s friend Emily tells him about the invisible leash that connects people to their pets after the death of a beloved animal.

Major Impossible

by Nathan Hale (Abrams/Amulet, Dec. 3, $13.99, ISBN 978-1-4197-3708-4)

This ninth book in the middle grade nonfiction graphic novel series Nathan Hale’s Hazardous Tales shares the life of Major John Wesley Powell, an intrepid one-armed geologist. In 1869, Powell journeyed with an expedition of 10 men and four boats in an effort to be the first down the Colorado River, mapping the Grand Canyon.

Off I Go!

by Kelly Greenawalt, illus. by Amariah Rauscher (Scholastic/Acorn, Dec. 3, paper, $4.99, ISBN 978-1-338-34003-7)

After I Am a Super Girl!, the first early reader starring Princess Truly, Princess Truly’s magic curls allow her, Sir Noodles the Pug, and her younger brother Ty to travel to the South Pole. Truly and Noodles then fly to an island, the city, and the rainforest before heading home.

The Crims at Sea

by Kate Davies (HarperCollins, Dec. 10, $16.99, ISBN 978-0-06-249416-0)

The final installment of The Crims middle grade trilogy, after Down with the Crims!, features more hijinks for Imogen Crim and her family of bumbling criminals. When Imogen is bored on her family vacation in Dullport, her enemy-turned-best-friend Ava Kruk comes to her rescue in a stolen submarine. But the duo must team up to fight the Gull when the supervillain lures the Crims to his island lair.

I Love You, Fred

by Mick Inkpen, illus. by Chloë Inkpen (S&S/Aladdin, Dec. 10, $17.99, ISBN 978-1-5344-1475-4)

What’s in a name? The father-daughter team behind I Will Love You Anyway offers another tale highlighting the small, mischievous sweatband-wearing dog, who ponders the meaning of “Fred.”

Kat Wolfe Takes the Case

by Lauren St. John (Farrar, Straus and Giroux, Dec. 10, $17.99, ISBN 978-0-374-30961-9)

In this second book of the Wolfe and Lamb Mysteries middle grade series, after Kat Wolfe Investigates, the 12-year-old petsitter-cum-detective returns, along with her best friend Harper Lamb and their animal sidekicks. When a dracoraptor skeleton is uncovered—along with the remains of a man who has been missing for two years—the sleuths take on the case.

Mac Cracks the Code

by Mac Barnett, illus. by Mike Lowery (Scholastic/Orchard, Dec. 26, $12.99, ISBN 978-1-338-59423-2)

Following Top Secret Smackdown, this fourth book continues the illustrated Mac B. Kid Spy series. The latest adventure finds Mac resuming his role as a spy for the Queen of England, traveling from California to England to France to Japan to New York City. With the Queen’s corgi Freddie by his side, Mac attempts to decode secret messages, goes rogue, and faces his nemesis, the KGB Man, at the Video Game World Championships.

The Return of Thelma the Unicorn

by Aaron Blabey (Scholastic, Dec. 26, $14.99, ISBN 978-1-338-60889-2)

This rhyming picture book sequel to Thelma the Unicorn showcases Thelma’s comeback as the eponymous international sensation with the help and support of Otis, her best friend.

Lola Dutch I Love You So Much

by Kenneth Wright, illus. by Sarah Jane Wright (Bloomsbury, Dec. 31, $17.99, ISBN 978-1-5476-0117-2)

The third Lola Dutch picture book, after Lola Dutch When I Grow Up, heralds the return of Lola Dutch and her pals. When Gator, Crane, and Pig are each having grumpy mornings, Lola Dutch knows exactly how to cheer them up. But after Lola realizes she forgot Bear, she must figure out the perfect way to remind him she loves him too.