We were stranded in rural Tongzhou last weekend on routine business, when we found ourselves surrounded by a horde of undead construction workers. As they lurched towards us for the kill, Echo sprang into action. "Call Popup Towers," she cried as she lobbed her phone through the air. "Get Gail to send reinforcements, and get a move on it!" In the next breath, she readied her Glock C22 for action.Impressed as I was with Echo's taste in sidearms, my heart sank as I looked at her cellphone. It had been a long day, and Echo's incessant texting had reduced the battery to a single bar of health. As the shuffling zombies drew nearer, I considered that there was a valuable lesson somewhere here about the perils of a life dependent on consumer electronics, and the dangers of leaving the house without a reliable supply of spare batteries.