The Walking Dead, by Robert Kirkman and Charlie Adlard.
Our heroes have scattered after the shocking events of issue 48. Lori and Judith are dead. Tyreese is dead. The prison is not safe after the battle with the Governor, and the crew breaks off into different cliques, some of which meet back up in further issues. Being mostly on foot, there is only so far that the crew can wander off, even in different directions. The coincidence of them meeting back up again can be overlooked.
We see that everyone is going more than a little bit crazy, even Rick. Especially Rick, in this volume. He spends the first few issues having imaginary conversations with his dead wife on a broken phone, shades of Michonne ever since her introduction. The responsibility of leading this ragtag band have left him mentally vulnerable, and the berakdown he suffers in response to his wife's and daughter's death are not unexpected. Writer Robert Kirkman does an excellent job of making Rick's instability believable.
The scenes following on, where Rick takes too many painkillers and drops into a delirium, were very interesting. Even as a veteran comic book reader, I was not sure exactly when he had awoken. For a while, I was not dismissing the possibility that three complete issues were Rick's dream-state, but that was not the case.
The biggest plot movement in this series of issues is Rick and his crew finding Abraham and his scientist buddy, who believes he knows what caused the zombie outbreak. This small group is heading to Washington, and Rick and his ever-shrinking crew team up with them. But life on the road is inherently unsafe, especially now that the zombies are moving in herds.
This change in zombie behavior, the notion that they may be learning or at the very least adapting, is interesting. I don't know if Kirkman has an idea of what the "origin story" of the outbreak was, or if he ever plans to disclose it us. But these changes in zombie behavior do not bode well for our heroes.