From 2009 to 2010, poliovirus crossed from India to Nepal and back to India again, hitching a ride inside an unsuspecting body and paralyzing children on arrival. With polio on the run in its other traditional strongholds in Inida Uttar Pradesh and its conservative neighbourhoods, the remote and waterlogged Kosi River Basin and the tangled slums of West Bengal - the polio partners turned their attention to Jogbani and the other 41 crossing towns strung along the Nepali border. But as it turned out, vaccinating every child on the border wasn't as easy as it had seemed...