Tanker the Defender (Book Two of Doggie Heroes Series)

Tanker was once in the K-9 division of his master's army unit. But that was long ago, his master had gone away never to be seen again.
Now Tanker had another job. He was to look out after all the dogs in the neighborhood and keep them safe. When Pug the bulldog could
no longer fit in his mister's door, it was time to search out food elsewhere. He knew where to go. Tanker would help him. And Tanker did
feed Pug. Until Pug's mister got sick. Sam the Beagle, kept Tanker informed of Pug's life. But Pug was a lot like Tanker, he was very attached
to his mister.