The first order - Jeff Abbott

The darkest day of Sam Capra's life was when he watched his brother,
Danny, executed by extremists in an online video. But now, evidence has
surfaced that Danny may still be alive - leading a secret, hidden life
for the past six years while the world believed him to be dead. What's
more, Sam discovers that Danny may be plotting a murder that could
change history: assassinating the Russian president.

Determined
to stop his brother from committing a murder that may cause a terrible
war, Sam goes undercover in a one-man mission to save the world - and to
save his brother.

Packed full of action and twists,The First Order is an addictive,
exhilarating thriller that shows
international bestseller Jeff Abbott at the height of his powers.