Time Cures. Time Adventures Series, #4

Bradley Connors and James Garrett are back in London more than a year after their last time-traveling adventure. Bradley has been summoned back to work on a new campaign for his biggest international client, BritCom. While his husband is busy, James heads off to visit with the granddaughter of his old friend, Penelope, whom he'd left behind in the past. While reminiscing, James discovers that Penelope suffered through some difficult financial hardships after he'd abandoned her and the rest of his friends.
With the regrets about his hasty decision to join Bradley in the future, and his seeming abandonment of Penelope, still lingering in his thoughts, James heads back towards the City. That's when a sudden thunderstorm blows up out of nowhere and a bolt of lightning hits the brickwork arch he had ducked under to try and escape the rain. When he wakes up, it's clear James isn't in 2017 London anymore.
Thus begins another adventure in the past, with our boys battling a polio outbreak in 1956 London in another race against time to save their friends and redeem their past.