they are dereck and beverly joubert. filmmakers, big cat protectors and partners in every conceivable way. sometimes dereck jumps into the. >> salted water, straight from the delta. >> reporter: occasionally, beverly will cook for guests. but almost every day for 30 years, these high school sweethearts have been alone together in the wild. >> the longest we went without seeing anybody at all was 270 days, i think. and then we needed to get out. >> reporter: yeah. you know, you should do a film on marriage. because i don't know a lot of couples that could live out here for 270 days and still stay together. >> well, maybe that's the answer. you do have to. you have to have that time without society around you. >> reporter: that's it. a lifetime ago they left south africa in search of edadventure. became smitten with the big cats and never went back. each dawn, they load up their four-wheel drive office and take that swampy commute against this delta. they head past monitor lizards, around the yawning hippos. take a left at